25 Buick fuel problems

[carmover]

I think I have finally figured my 25 Buick problems out.I put a new electric pump on it and it is still doing the same thing.It will start right up and run smoothly for  few minutes and then start backfiring and popping and running real rough and then shuts off completely. I removed the float bowl cover and watched the float and as long as it had fuel in the bowl it ran and then the fuel would start bubbling in the float bowl and then it would start running bad.I think it is sucking air at the banjo fitting on the fuel pick up tube I took it out and it has one worn out copper washer on it .I need to find a couple of crush washers to put on that fitting if I can figure out the correct size is.I haven't been able to find any local and Restoration Supply has every size .I just need to know what size to order.

[Hubert_25-25]

Ron, 

       Do you have a digital caliper.    I use mine all the time.  They are $20 at Lowes.  If you can, find a stainless one as they are a little more durable than the plastic ones. 

I like the copper crush washers, but I also like the red fiber washers.  My Jaguar uses red fiber washers as OEM on the fuel line and you may have better luck sealing with these.  www.restorationstuff.com carries both washer styles.  One thing about these Banjo fittings is that they also have to be really tight to do a good job.  #2 non hardening permatex is also supposed to be fuel proof (but check that), and you could put that on both sides of the washer.   

Burlen.co.uk also sells all new banjo fitting parts in case any of the ones you have are questionable.  

http://burlen.co.uk/

 

Hugh

 

Edited May 22, 2018 by Hubert_25-25 (see edit history)

[carmover]

3 hours ago, Hubert_25-25 said:

Ron, 

       Do you have a digital caliper.    I use mine all the time.  They are $20 at Lowes.  If you can, find a stainless one as they are a little more durable than the plastic ones. 

I like the copper crush washers, but I also like the red fiber washers.  My Jaguar uses red fiber washers as OEM on the fuel line and you may have better luck sealing with these.  www.restorationstuff.com carries both washer styles.  One thing about these Banjo fittings is that they also have to be really tight to do a good job.  #2 non hardening permatex is also supposed to be fuel proof (but check that), and you could put that on both sides of the washer.   

Burlen.co.uk also sells all new banjo fitting parts in case any of the ones you have are questionable.  

http://burlen.co.uk/

 

Hugh

 

 Thanks Hugh,I haven't got a digital caliper yet but I am in the market for one.I noticed Restoration Supply has an assortment box of red fiber washers and I might get one of those so I will have plenty of them in stock.I need to get it running in the next couple of days  and I have got to take it and get a new muffler installed by Friday.I have a special show close to where I live and I want to take both old Buicks to the show and display them together.The 23 Got Best Patina Award last Saturday at a 300 car show in Leeds Alabama. 

[sligermachine]

I found copper crush gaskets in a ''Auto zone' store had packages of 9   per pack copper crush seals  3 fit the gas lines on my 1925 tank 'in that pack I bout 2 packs at a price of 8.00  hanged on a rod on the floor . I was glad I found them .I had been  looking for a wile .  11/16 inside dia. and 7/8 out side  .060 thick but thicker would work also .  ------------------- Do not cheek tank fittings with air pressure by putting air in tank-------------------------  it will not hold up to air pressurize AT ALL    

[carmover]

8 hours ago, sligermachine said:

I found copper crush gaskets in a ''Auto zone' store had packages of 9   per pack copper crush seals  3 fit the gas lines on my 1925 tank 'in that pack I bout 2 packs at a price of 8.00  hanged on a rod on the floor . I was glad I found them .I had been  looking for a wile .  11/16 inside dia. and 7/8 out side  .060 thick but thicker would work also .  ------------------- Do not cheek tank fittings with air pressure by putting air in tank-------------------------  it will not hold up to air pressurize AT ALL    

Thanks Kyle, I learned that about the air test the hard way a few years back. When I tried it I crushed the vacuum tank float.I will try auto zone and see if they have them.

[carmover]

I am still frustrated! I found some fiber washers close by and sealed the fuel tank Banjo Fitting and to my delight the old girl came to life and I adjusted the carb and it idled smoothly and ran very well but had a slight hesitation when I stepped on the pedal.So I had the fuel valve open 1 turn and lined up with the post and began slowly opening up the air until it had good throttle response and was running and idling nicely.I thought I had finally fixed the problem and the car ran smoothly for over an hour.I decided to take the car on a short drive down my driveway and about 50 feet down it started back firing through the muffler and running like it  would if you pull the choke out on a hot engine.I took it back to the shop and checked all of the valves and found three that were a little tight.After readjusting them the car started right up and ran perfectly.I had the float bowl cover off and observed the float and it was working properly and metering like it should.It ran for an hour or so  I got in to pull it back in the shop thinking I had finally fixed the problem but when I stepped on the pedal it started backfiring through the muffler and running rough and finally shut off and would not restart.I already rechecked the valves while the car was running and they are perfectly adjusted.This is very frustrating indeed!

[dibarlaw]

Ron:

 My heart goes out to you as that is what my car was doing. The only difference was that I was running the rebuilt vacuum tank. That was before the oil leak at the back of the head precipitated my engine rebuild. I am still waiting since they have had my engine since September. Last check they were waiting on pistons from Ross. Whatever the final solution is I hope I will learn from your frustrations.

[carmover]

Thanks Larry,I was wondering about you the other day how your engine job is coming along.I went down tonight after dinner and it cranked right up and ran perfectly and I got it all detailed tonight and am ready to get a new muffler installed but I am afraid to  because as bad as it was back firing this morning it would have blown another muffler off.It has to be some small thing that it is doing because it is running so good and then starts to do that.It could be something as simple as trash in the fuel system.

[hchris]

4 hours ago, carmover said:

I stepped on the pedal it started backfiring through the muffler and running rough and finally shut off and would not restart.

 

If I could perhaps add my thoughts here; you mention the above aspect twice in your observations, before and after playing with the carb.

 

My first impression is that the stumbling with exhaust backfires ( technically after fire) is indicative of an excessive rich mixture, particularly when you get to the point where it wont start, I suspect its flooded at that point, taking the plugs out should reveal this as they will probably be black and sooty.

 

If this is the case then you need to establish why its flooding, you say that it ran ok for an hour (I`m  assuming that the car was stationary). So two things come to mind:

1. the transition from idle to opening the throttle could mean that jets/mixture adjustments are not correct;

2.( this I find more likely as you say you have added an electric pump), is that as you open the throttle and the float level drops, the pump, in trying to meet the increased demand overwhelms the float/needle valve and floods the carb. 

 

Have you checked the pressure output of the pump ?  A vacuum tank fed carb was designed to run at 0.5 psi delivery pressure, the average output of an electric pump is somewhere between 1.5 and 3 psi and could even be higher depending on the pump. At idle with minimal demand from the pump the float may manage to hold the needle on its seat, but once you reach a point where pump demand increases and the float is jiggling around with the float level changing attitude when in motion, it could well be that the mechanism  is incapable of shutting off the pump flow.

[hchris]

On 5/22/2018 at 7:59 AM, carmover said:

the fuel would start bubbling in the float bowl

 

Just noticed this from your first post; could this also be an indicator of the float struggling to hold the needle on its seat ?

[carmover]

1 hour ago, hchris said:

 

Just noticed this from your first post; could this also be an indicator of the float struggling to hold the needle on its seat ?

My carb has been modified to handle up to 3 psi of fuel pressure and I run a Holley Drag Racing Regulator.I have a new pump that is rated at 4 psi and to adjust the pressure I turn it in until the needle can't hold the pressure and back it off until the needle shuts the fuel off. it doesn't seem to be flooding and is replenishing the fuel properly and I adjusted the air until the engine ran perfectly and had good throttle response.In my earlier post. I mentioned that it was bubbling in the float bowl.That was actually air bubbles and it wasn't getting much fuel.It was sucking air at the banjo fitting on the tank.I fixed that problem and it is now getting plenty of fuel.As you said it is probably running a little rich.I also have ran the car not just at idle but at speed after the hesitation in the throttle response.I also leaned it out enough to have smooth running and good throttle response and it ran like it was supposed to.Tonight it is running great and I drove it to the end of my 900 foot driveway and back and it didn't miss a beat.It has been running cool and has good oil pressure and it starts right up.But Tomorrow it may run good or start this mess over again. 

[maok]

Check your fuel tank cap, is it ventilated or blocked?

[carmover]

8 hours ago, maok said:

Check your fuel tank cap, is it ventilated or blocked?

The fuel cap has been checked and is vented properly,I even removed the cap one time when it was having one of these problems and it didn't help.

[27donb]

Fuel related issues can be similar in nature to ignition system issues. 

 

I chased a stumble and die condition for weeks, thinking it was fuel.  Turns out, bad ignition coil. 

 

On the positive, now my carb is rebuilt and clean. 

[carmover]

When I parked it last night it was running nicely no misses and great throttle response and it cranked right up .I drove it to the end of my long driveway and back with no problems.This morning it cranked right up and ran great.I backed it out and ran it at a fast idle for about 10 minutes running nicely and then suddenly it started that problem running terrible.It will barely runs and sometimes will shut down.It won't backfire at idle but if you open up the throttle up it will backfire through the muffler.I shut it off and about 20 minutes later I cranked it up and it ran a little rough at first but suddenly smoothed out and ran perfectly and raced up nicely with good throttle response.In a few minutes it started running rough again .

[Guest]

"Afterfire" in the muffler is usually too rich.  "Backfire" through the carb is usually too lean.

[J.H.Boland]

Have the fuel lines been replaced or cleaned out ? A flake of rust stuck in the line can act like a butterfly valve,sometimes blocking and sometimes not.

Like 27donb,I found that my '29 Buick had issues other than fuel. A defective coil was one issue. The corroded contacts in the ignition switch was another problem.The car ran great but would suddenly cut out ,just long enough to fill the muffler with fuel.It would then start again,blowing the muffler wide open.That's exciting,right under your seat.After two seamed mufflers blew, we replaced them with a Cherry Bomb.If it misbehaves again,it will just blow a flame out the tailpipe !

It is frustrating, but after finally getting in touch with some knowledgeable people on this and other forums, the uneventful drives make it all worthwhile.

[Grimy]

Even though your carb has allegedly been modified to handle 3 psi or more fuel pressure, just TRY this:  Turn your Holley pressure regulator down to 1 (preferably) or 2 psi.  And where is the regulator located in the fuel system?  Rationale:  Carb seems to be getting more pressure, and thus volume, than it can handle.  Those carbs were designed for GRAVITY flow (about 1 psi if that).  I can't understand why you'd find it advantageous to give a slow-turning engine so much fuel pressure and volume.

[carmover]

3 hours ago, Grimy said:

Even though your carb has allegedly been modified to handle 3 psi or more fuel pressure, just TRY this:  Turn your Holley pressure regulator down to 1 (preferably) or 2 psi.  And where is the regulator located in the fuel system?  Rationale:  Carb seems to be getting more pressure, and thus volume, than it can handle.  Those carbs were designed for GRAVITY flow (about 1 psi if that).  I can't understand why you'd find it advantageous to give a slow-turning engine so much fuel pressure and volume.

 

3 hours ago, Grimy said:

Even though your carb has allegedly been modified to handle 3 psi or more fuel pressure, just TRY this:  Turn your Holley pressure regulator down to 1 (preferably) or 2 psi.  And where is the regulator located in the fuel system?  Rationale:  Carb seems to be getting more pressure, and thus volume, than it can handle.  Those carbs were designed for GRAVITY flow (about 1 psi if that).  I can't understand why you'd find it advantageous to give a slow-turning engine so much fuel pressure and volume.

Grimy I did that because the vacuum tank drove me crazy for more then 10 years.I rebuilt it and could never get it to shut off it was sucking raw fuel through the vacuum tube straight into the intake..The old worn out engine was happy with this electric set up but the new engine doesn't like it.I found that it is in fact flooding big time.I put my old fuel pump back on and have adjusted the regulator all the way back and it is still flooding .I think it is a carb issue or a regulator issue.The carb is set to handle up to three pounds of pressure.When I switched it over to the electric pump it ran a whole lot better and never would flood and you didn't need to turn off the fuel every time you stopped and you could go up long hills without it trying to run out of fuel.For the first time I could drive the car more than a block before getting scared and going back home.

[carmover]

3 hours ago, J.H.Boland said:

Have the fuel lines been replaced or cleaned out ? A flake of rust stuck in the line can act like a butterfly valve,sometimes blocking and sometimes not.

Like 27donb,I found that my '29 Buick had issues other than fuel. A defective coil was one issue. The corroded contacts in the ignition switch was another problem.The car ran great but would suddenly cut out ,just long enough to fill the muffler with fuel.It would then start again,blowing the muffler wide open.That's exciting,right under your seat.After two seamed mufflers blew, we replaced them with a Cherry Bomb.If it misbehaves again,it will just blow a flame out the tailpipe !

It is frustrating, but after finally getting in touch with some knowledgeable people on this and other forums, the uneventful drives make it all worthwhile.

I have cleaned all of the fuel lines from the pickup tube all the way to the carburetor.I think it is a problem in the carb itself where the needle and seat are not shutting off the fuel.I took all the fuel out of the fuel bowl and turned on the pump and watched the float come up and started the car and it ran great for a few minutes and started running rough and I checked the float and fuel was rising above it.I am fixing to pull the carb and clean it and check and see why it is not shutting off.

[Grimy]

Please TRY my suggestion above (it will take less than five minutes, and you can quickly change it back if it doesn't solve the problem);  I always attempt the quickest, easiest, and least invasive procedures first.  Personally, I'd rebuild the vacuum tank and use that without the electric pump, as I have on my 1922 Paige and 1925 Pierce.  Do you still have the original carb parts to re-install if all else fails?

 

A day or more ago, someone proposed a theory on why/how the pump overloads the needle valve/seat when driving rather than idling.

 

As soon as you do get this problem solved, please change the oil which is probably very diluted with gasoline by now.

[carmover]

10 minutes ago, Grimy said:

Please TRY my suggestion above (it will take less than five minutes, and you can quickly change it back if it doesn't solve the problem);  I always attempt the quickest, easiest, and least invasive procedures first.  Personally, I'd rebuild the vacuum tank and use that without the electric pump, as I have on my 1922 Paige and 1925 Pierce.  Do you still have the original carb parts to re-install if all else fails?

 

A day or more ago, someone proposed a theory on why/how the pump overloads the needle valve/seat when driving rather than idling.

 

As soon as you do get this problem solved, please change the oil which is probably very diluted with gasoline by now.

George,I have backed the pressure all the way off and it is still flooding.I never said I was running three pounds I said it was set up to handle up to three pounds.I run a whole lot less pressure than that.I will never go back to the vacuum tank I hate that system.I am pretty sure the problem is going to be in the carburetor and not the pump and regulator.

[maok]

What carb is it? What do your spark plugs look like when it starts to run rough? How do you know its flooding?

[Grimy]

6 minutes ago, carmover said:

George,I have backed the pressure all the way off and it is still flooding.I never said I was running three pounds I said it was set up to handle up to three pounds.I run a whole lot less pressure than that.I will never go back to the vacuum tank I hate that system.I am pretty sure the problem is going to be in the carburetor and not the pump and regulator.

Do you have the parts to put the carb back to original?  Or another carb, even a loaner from someone in your area, that you can substitute?  After all you've gone through so far, I really think that substituting a known good component is much better than tweaking what you have.

 

Short-term Plan B:  Use an outboard's portable tank, position it on the cowl or roof, hook up rubber hose, and let gasoline flow by gravity.  If you still have the problem, it's not the supply pressure but MAY be the carb.  If the problem is resolved, it's a supply pressure issue.

 

Again, WHERE is your Holley regulator located in the system?

[carmover]

14 minutes ago, Grimy said:

Do you have the parts to put the carb back to original?  Or another carb, even a loaner from someone in your area, that you can substitute?  After all you've gone through so far, I really think that substituting a known good component is much better than tweaking what you have.

 

Short-term Plan B:  Use an outboard's portable tank, position it on the cowl or roof, hook up rubber hose, and let gasoline flow by gravity.  If you still have the problem, it's not the supply pressure but MAY be the carb.  If the problem is resolved, it's a supply pressure issue.

 

Again, WHERE is your Holley regulator located in the system?

The regulator is under the drivers side floorboard.It ran for years with no problems.I am going to gravity test it tomorrow and see if it will run.I am suspecting the needle and seat or possibly the regulator.One thing that points to the carb is the regulator is all the way backed off and it should not be getting any fuel at all yet it is still flooding.

[carmover]

I don't have any other parts or carb to replace it, I have to use what I got.The carb was rebuilt three years ago and was running fine before the engine rebuild this last winter.

[Spinneyhill]

11 minutes ago, carmover said:

One thing that points to the carb is the regulator is all the way backed off and it should not be getting any fuel at all yet it is still flooding.

You'll have to help me out here. From what you just said, I thought if the regulator was closed, NO fuel should be getting to the carb? Might the problem be with the regulator?

[Grimy]

11 minutes ago, carmover said:

One thing that points to the carb is the regulator is all the way backed off and it should not be getting any fuel at all yet it is still flooding.

Or the regulator--although I have the Holley 12-804 (? - from memory) regulators on my supplemental pumps on my 1930 and 1934 cars equipped with mechanical factory pumps and they have been perfect.  The gravity test will tell us a lot.

[dibarlaw]

I had mentioned all of these symptoms long ago on a similar thread about my 1925 Standard with the original Marvel carb. The only thing that got it running better at the time was to eliminate the electric pump and crappy pressure regulator that came with my car and rebuild the vacuum tank. Ron's car though has had the carb modified and has a better pressure regulator. I also went thru a bad condenser as a partial cause and also changed out the Coil. I checked and re checked the inner tube in the heat riser for leaks and all the heat had been blocked off to the riser unit. Hugh sent me his carb to try and the car ran the same. I re checked my carb and found I had to refit the dashpot valve tail clearance to the venturi block again. Each job got a bit better response, but the car could still not drive down the road with out constant messing with the carb. Doing a vacuum check it was no where steady for a reading.. Checked manifolds for leaks etc. It was to a point that I could only drive it about 10 minutes before the same old symptoms showed up again. (Things getting warmed up.)

 Of course the last time was when I found the oil leak from the rear of the head pouring on the hot exhaust pipe. (much smoke) As I am still waiting for my engine to get back form Reeve's There is nothing for me to ad to help Ron in his problems.

  One thing that both Hugh and I found that the valve springs on both of our engines were a mix and match of various heights. A few of mine were 1/2" difference in height and the compressed height pressures varied as much as 15 lbs. with the highest pressure heights around 50lbs. The valve lifter springs are to be 40-52lbs at a height of 1 25/32".  Shop Manual indicates correct valve spring pressure is to be 80 to 88lbs. at a compressed height of 2 1/32". So to me the valve springs that were on my car were very weak indeed.

 Just some added thoughts.

[carmover]

1 hour ago, maok said:

What carb is it? What do your spark plugs look like when it starts to run rough? How do you know its flooding?

I know it is flooding because I had the cover off of the float bowl and when the float came up it didn't stop the fuel.I watched the fuel cover up the float a continued to rise .Itook a shop towel and soaked all of the gas out of the carb and cranked the car and it ran great as long as the gas level is right but when the float was all the way up and fuel kept coming in that's when the rough running started.Either the regulator is not lowering the fuel pressure or the needle is not seating.I am running the original 25 marval carb that has been modified to handle the electric pump.

Edited May 24, 2018 by carmover (see edit history)

[carmover]

38 minutes ago, dibarlaw said:

I had mentioned all of these symptoms long ago on a similar thread about my 1925 Standard with the original Marvel carb. The only thing that got it running better at the time was to eliminate the electric pump and crappy pressure regulator that came with my car and rebuild the vacuum tank. Ron's car though has had the carb modified and has a better pressure regulator. I also went thru a bad condenser as a partial cause and also changed out the Coil. I checked and re checked the inner tube in the heat riser for leaks and all the heat had been blocked off to the riser unit. Hugh sent me his carb to try and the car ran the same. I re checked my carb and found I had to refit the dashpot valve tail clearance to the venturi block again. Each job got a bit better response, but the car could still not drive down the road with out constant messing with the carb. Doing a vacuum check it was no where steady for a reading.. Checked manifolds for leaks etc. It was to a point that I could only drive it about 10 minutes before the same old symptoms showed up again. (Things getting warmed up.)

 Of course the last time was when I found the oil leak from the rear of the head pouring on the hot exhaust pipe. (much smoke) As I am still waiting for my engine to get back form Reeve's There is nothing for me to ad to help Ron in his problems.

  One thing that both Hugh and I found that the valve springs on both of our engines were a mix and match of various heights. A few of mine were 1/2" difference in height and the compressed height pressures varied as much as 15 lbs. with the highest pressure heights around 50lbs. The valve lifter springs are to be 40-52lbs at a height of 1 25/32".  Shop Manual indicates correct valve spring pressure is to be 80 to 88lbs. at a compressed height of 2 1/32". So to me the valve springs that were on my car were very weak indeed.

 Just some added thoughts.

Larry' Mine has a Rochester needle and seat set up that has worked great for years until now.My 23 Buick still runs it's vacuum tank but is filled with an electric pump and regulator and works perfectly.I think I am on the right trail as I am watching it flood so it has to be a bad regulator or the needle and seat are not stopping the flow at any pressure.When the fuel is at the right level the engine runs perfectly.I bought all new valve springs from Egge and have all new valves and Bronze valve guides and hardened valve seats.I also replaced that busted upper casting so I don't have a busted block anymore.

Edited May 24, 2018 by carmover (see edit history)

[carmover]

1 hour ago, Spinneyhill said:

You'll have to help me out here. From what you just said, I thought if the regulator was closed, NO fuel should be getting to the carb? Might the problem be with the regulator?

I am thinking the same thing .I ran the regulator out to it's last thread and at that point it should not have any fuel to the carb yet it is still flooding. I am going to set up a temporary gravity flow set up as George has suggested Tomorrow and that should tell us a lot . 

[Terry Wiegand]

Ronnie, I want to throw something out here that you may not have considered.  As everyone on here knows, I have three of the caged-valve model Buicks.  The 1916 doesn't enter in the discussion because it isn't back on the road yet.  However, the 1920 and 1922 are the ones that can relate to your ongoing problems.  I have had John Wolf out in Ohio rebuild the vacuum tanks on all three cars.  Got the one back for the '20 and the car ran worse (if you call belching, backfiring, and running like crap) than before the rebuild.  I sent it back to him and they discovered that the two springs in the canister cover were not shutting off the vacuum  to the tank.  The result was that raw gasoline was being sucked into the intake manifold ABOVE the carburetor.  The springs were replaced and that problem went away.  However, the engine would periodically go through one of those belching, backfiring fits that would drive a person to the edge of insanity.  We took the car up to the McPherson College Car Show three weeks ago.  Before we went, I installed a set of NOS AC Titan spark plugs that were gapped to the .030" that the reference manual called for.  I also removed the distributor cap and rotor and these were very thoroughly cleaned and checked visibly under a magnifying glass for any cracks.  They checked out great.  I removed the 99 year old plug wires that were as hard as a rock.  I replaced the wires with new Black rubber, solid core wiring with Nickel Plated Rajah plug terminals.  The Reference Manual calls for coating the distributor cap track with petroleum jelly.  That would be Vaseline to us common folk.  I applied it liberally.  I checked the points gap while I had things opened up.  Right where it should be.  Applied LubriPlate White Grease to the point cam with a Q-Tip.  Those things work great for stuff like that.  Installed a new 6-Volt battery.  Made sure that all of the connections were clean and tight.  It was time for that proverbial Firestone moment - you know - where the rubber hits the road.  I turned the ignition switch lever - the starter/generator is doing its motoring thing - I stepped down on the starter pedal - and if I'm lyin' I'm dyin', the engine turned over less than two revolutions and settled down into the sweetest idle that I have ever heard that engine do.  It runs as smooth as silk with instantaneous throttle response.  We put about 5 miles on the car before heading up to the show.  The car ran flawlessly - you know - like a new Buick should.  The point I am making here is this - do not dismiss checking out the ignition system.  I think that I found out that electrical problems can mimic carburetion issues.  I certainly hope that what I did with the engine will go a long way in helping it run better and smoother.  Time will tell.  I am extremely optimistic - after all, this is a Buick for cryin' out loud.  And it has less than 5,000 actual miles on the clock since new.  That's my story here for what it's worth.

 

Terry Wiegand

South Hutchinson, Kansas

[carmover]

9 hours ago, Terry Wiegand said:

Ronnie, I want to throw something out here that you may not have considered.  As everyone on here knows, I have three of the caged-valve model Buicks.  The 1916 doesn't enter in the discussion because it isn't back on the road yet.  However, the 1920 and 1922 are the ones that can relate to your ongoing problems.  I have had John Wolf out in Ohio rebuild the vacuum tanks on all three cars.  Got the one back for the '20 and the car ran worse (if you call belching, backfiring, and running like crap) than before the rebuild.  I sent it back to him and they discovered that the two springs in the canister cover were not shutting off the vacuum  to the tank.  The result was that raw gasoline was being sucked into the intake manifold ABOVE the carburetor.  The springs were replaced and that problem went away.  However, the engine would periodically go through one of those belching, backfiring fits that would drive a person to the edge of insanity.  We took the car up to the McPherson College Car Show three weeks ago.  Before we went, I installed a set of NOS AC Titan spark plugs that were gapped to the .030" that the reference manual called for.  I also removed the distributor cap and rotor and these were very thoroughly cleaned and checked visibly under a magnifying glass for any cracks.  They checked out great.  I removed the 99 year old plug wires that were as hard as a rock.  I replaced the wires with new Black rubber, solid core wiring with Nickel Plated Rajah plug terminals.  The Reference Manual calls for coating the distributor cap track with petroleum jelly.  That would be Vaseline to us common folk.  I applied it liberally.  I checked the points gap while I had things opened up.  Right where it should be.  Applied LubriPlate White Grease to the point cam with a Q-Tip.  Those things work great for stuff like that.  Installed a new 6-Volt battery.  Made sure that all of the connections were clean and tight.  It was time for that proverbial Firestone moment - you know - where the rubber hits the road.  I turned the ignition switch lever - the starter/generator is doing its motoring thing - I stepped down on the starter pedal - and if I'm lyin' I'm dyin', the engine turned over less than two revolutions and settled down into the sweetest idle that I have ever heard that engine do.  It runs as smooth as silk with instantaneous throttle response.  We put about 5 miles on the car before heading up to the show.  The car ran flawlessly - you know - like a new Buick should.  The point I am making here is this - do not dismiss checking out the ignition system.  I think that I found out that electrical problems can mimic carburetion issues.  I certainly hope that what I did with the engine will go a long way in helping it run better and smoother.  Time will tell.  I am extremely optimistic - after all, this is a Buick for cryin' out loud.  And it has less than 5,000 actual miles on the clock since new.  That's my story here for what it's worth.

 

Terry Wiegand

South Hutchinson, Kansas

Thanks Terry, When I was using the vacuum tank mine was sucking gas straight into the intake manifold .I installed the rebuild kit from Bob's which included new springs and that didn't help.Mine is flooding big time .It will fill the float bowl completely up above the float.It was running rough last night and gas was coming out of the vent button.I don't know if this is the only problem I have but it is certainly a problem.I also noticed that this all starts when the fuel start rising above the float.I am suspecting the regulator because with the pressure backed completely off it is still getting fuel to the carb and flooding.

[Mark Shaw]

IMO, the fuel pump and regulator should not be used with a functioning vacuum tank.

Turn off the electric pump, remove the regulator, and see if it runs correctly with a full vacuum tank.  If it does run correctly, turn on the electric pump only when needed to resolve vapor lock or initial start after winter storage.  The regulator will not be needed.  

[Terry Wiegand]

I had a 1928 Willys-Knight that had an electric fuel pump in the line between the gasoline tank and the vacuum tank.  I only used it occasionally to fill the vacuum tank if the car sat for a while between driving trips.  Mark is right, if things are adjusted right, one doesn't need a fuel pump.  The vacuum tank system was really very trouble free when everything was set properly.

 

Terry Wiegand

South Hutchinson, Kansas 

[Bob Engle]

My 1917 D45 has an electric fuel pump and regulator feeding gas into the vacuum tank.  The vacuum line to the intake manifold is plugged.  A return line is run from the vacuum tank back to the gss tank.  I put a pressure gauge on the vacuum tank fill plug and the system maintains less than  1/2# pressure in the tank, so there should be about 1# at the carb.  The system seems to work fine.  I had some  stumbling problems on acceleration, so I went into the  tdistributor and found that some previous owner had replaced the  points cam block with a homemade one that was 3 times thicker  which changes the whole dwell picture.  I also  found that the advance fly weights were sticking,  so I pulled the distributor appart  and cleaned an lubed the mechanical advance.  I do plan to put the vacuum tank back into operating condition sometime in the future.  I picked up a spare at Hershey so I now have all the internal parts.  As for carmover's problem, I would seriously look at the needle valve and seat.  Put a piece of thread around the float and pull up when it is flooding and see if the flooding stops.  

 

Bob Engle

[Brian_Heil]

I'm in agreement with all those above, anytime the fuel is overcoming the float and the needle valve you have a problem.  Either too much pressure and the needle/seat/float is being overwhelmed or a bad float/needle/seat.  Run it just on a gravity feed from a secondary source at the height of the vacuum tank or just fill the tank with no feed from the pump and that fuel line removed and see what happens.  You may have additional issues, but I would resolve this one first.

 

I too have seen weak spark cause what seemed like fuel issues where the engine would not make power, only idle.  Bad coil, condenser, dirty points/rotor/cap/plugs, cracked cap.  Old wires.  Do you have a half inch long snapping spark at each cylinder?  One that will knock you back on your heels.  You should.  And you should be able to grab good plug wires with no fear of a shock if they are doing their job.

 

I've also had a broken ballast resistor wire and dirty/loose contacts at the ignition switch.

 

I've stated this several times and will state it again here.  I have seen two vehicle fires on tours in 22 years and both were associated with electric fuel pumps overwhelming carburetors that were never designed to handle the pressure of an electric pump and they could not regulate the pump low enough. We were in the middle of no where each time and both cars were a total loss.

 

Gasoline has a specific gravity of 0.70 (or in other words is only 70% the density of water)

 

26.678 inches of water equals 1 psi.  You memorize this about sophomore year, so trust me on this one.  So a column of water 26.678 inches tall in a tube at the bottom if you placed a gauge there would show 1 psi. 

 

18 inches = typical height of a vacuum tank over a carb. or measure yours and plug it in below.

 

18/27.678 = X/1  solve for X = .65 psi for a column of 18 inches of water.  Now multiply by Gasoline's specific gravity to give you the same head for gasoline.  0.65 psi x 0.70 = 0.455 psi,  an 18 inch column (or head) of gasoline creates less than a half psi.  That's all that old Marvel was ever designed to regulate and meter.

Edited May 25, 2018 by Brian_Heil (see edit history)

[Spinneyhill]

I have had flooding like this too. It occurs suddenly and things go poorly from then on. The problem was specs of dirt (rust?) under the needle, preventing it seating properly.

 

BTW, the needle is a smooth cone I presume? There is no shoulder cut into it by wear?

[Mark Shaw]

3 hours ago, Spinneyhill said:

 

BTW, the needle is a smooth cone I presume? There is no shoulder cut into it by wear?

Correct. 

You can also lap the needle/seat (or coin it with a light hammer tap when you are stuck on the side of the road).