carmover

25 Buick fuel problems

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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.

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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?

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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.

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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.

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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 by carmover (see edit history)

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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 by carmover (see edit history)

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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 . 

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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

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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.

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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.  

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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 

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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

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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 by Brian_Heil (see edit history)
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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?

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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).

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There are several items to consider concerning the amount of fuel pressure the carburetor will handle:

 

(1) Orifice of the fuel valve seat

(2) Effective pressure exerted by the float

(2A) Buoyancy of the float (material, and fuel volume displaced)

(2B) Mechanical advantage of the float (position of float arm, and type of float fulcrum).

 

While we have brass floats available for the early Marvels, the brass float does virtually nothing for buoyance (maybe a few percent). The brass float does have much better reliability than the original cork or the modern polynitraphyll (sp) closed cellular foam. Since the fulcrum position and style are unchanged, the float will exert only marginally more pressure.

 

Even if you are using the brass float, and have significantly reduced the fuel orifice; being from Missouri, I would have to be shown that this carburetor is capable of 3 psi, because of the fulcrum design and placement. However, not certain this is all of your problem.

 

As mentioned by others in this thread, ignition systems are less reliable than carburetors (even Marvel carburetors ;) )

 

Generally, a carburetor has very little personality. It will behave the same under similar conditions. The fact that the engine will idle, sometimes run, and then act weird to me indicates ignition issues. If the ignition is insufficient to fire the available fuel, then the plugs will be sooty just as if the carburetor was malfunctioning.

 

Unsure what tools you may have available to you. Readings from a clamp-on volt-meter on the plug wires when the engine is behaving, compared to when it is misbehaving would be interesting.

 

But just because some of us feel your coil may be suspect is not a REASON to change it! Ignition systems CAN be tested. Find a local friend or shop with an older Sun or Allen diagnostic oscilloscope (and knows how to use it) to hook up to the engine.

 

Jon

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3 hours ago, carbking said:

There are several items to consider concerning the amount of fuel pressure the carburetor will handle:

 

(1) Orifice of the fuel valve seat

(2) Effective pressure exerted by the float

(2A) Buoyancy of the float (material, and fuel volume displaced)

(2B) Mechanical advantage of the float (position of float arm, and type of float fulcrum).

 

While we have brass floats available for the early Marvels, the brass float does virtually nothing for buoyance (maybe a few percent). The brass float does have much better reliability than the original cork or the modern polynitraphyll (sp) closed cellular foam. Since the fulcrum position and style are unchanged, the float will exert only marginally more pressure.

 

Even if you are using the brass float, and have significantly reduced the fuel orifice; being from Missouri, I would have to be shown that this carburetor is capable of 3 psi, because of the fulcrum design and placement. However, not certain this is all of your problem.

 

As mentioned by others in this thread, ignition systems are less reliable than carburetors (even Marvel carburetors ;) )

 

Generally, a carburetor has very little personality. It will behave the same under similar conditions. The fact that the engine will idle, sometimes run, and then act weird to me indicates ignition issues. If the ignition is insufficient to fire the available fuel, then the plugs will be sooty just as if the carburetor was malfunctioning.

 

Unsure what tools you may have available to you. Readings from a clamp-on volt-meter on the plug wires when the engine is behaving, compared to when it is misbehaving would be interesting.

 

But just because some of us feel your coil may be suspect is not a REASON to change it! Ignition systems CAN be tested. Find a local friend or shop with an older Sun or Allen diagnostic oscilloscope (and knows how to use it) to hook up to the engine.

 

Jon

Jon,when I originally contacted Jeff Drybus [The old carb Doc] He asked if I was going to use the original vacuum tank or an electric pump.I told him that many had said that the marvel carb could not work with an electric pump and he assured me that he could modify the carb to handle the pressure.When I got the carb back and installed it and the new electric pump and regulator and filter and set the pressure at around 1 pound the engine cranked right up and ran perfectly.I could now finally enjoy driving the car any where I wanted to.It ran perfectly for years until I had to rebuild the engine.For several months the fuel system set dormant and the carb was on a shelf.Now the engine has been completely rebuilt and  all of the ignition system is brand new except the coil.As I have said before I can actually see it flooding and the engine cranks and runs perfectly as long as the fuel level is right but starts to run bad when the fuel starts covering up the float.I have tested the spark while this is going on and it still has a strong spark.I put a guage on the regulator last night and it is backed all the way out and is still registering nearly three pounds.It used to easily set to 1 pound so I think that is my problem.

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1 psi I can easily believe; really had an issue believing 3.

 

I think you have now found your problem.

 

I brought up the oscilloscope because of the 3 psi. I inferred from your post that the carb would stand 3. Wasn't convinced, but also didn't wish to argue. So the next logical place was voltage.

 

I am a firm believer in testing.

 

There are some incredibly knowledgeable helpful folks here that will try to help; but all of us are trying to "diagnose an upset stomach by telephone!". The more testing information which is provided helps reduce the number of possibilities.

 

Happy that you found the regulator issue. Enjoy that Buick!

 

Jon.

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Ronnie

 

How long are you going to keep us in suspense?

I'm anxiously waiting to decide if we should continue with ( restart?) our restoration or start on another car?

 

 

Brad

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Brad, I am moving kind of slow but am checking the carb out and have a new regulator coming.I hope this will fix the problem.I will let everyone know how it all works out!

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Ronnie,

I am kinda disappointed that you still want to have an electric pump in your car's fuel system.  I have had good luck with the simple vacuum system on several cars over a 45 year period.  If one gets everything set right they will run great.  You have to do what you feel is best for you.  We will wish you good luck with this Buick.

 

Terry Wiegand

South Hutchinson, Kansas

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Terry ,If you want to use the Vacuum Tank in your cars and it works for you then it is fine! As for me I struggled with the tank for years and spent a lot of money on it and could never get it to shut off.When I put the electric pump set up on it I drove the car 45 miles up and down hills and it never gave any problems and never flooded and you didn't have to open the hood and turn off the fuel supply every time you stopped.Up until I up graded it I drove the car 4 miles in 12 years.This 25 Buick has been nothing but trouble since I bought it But the electric pump gave me some enjoyment for a while.I do not have any patients left for that vacuum canister any more! If this doesn't fix it I am going to put it in my warehouse and rope it off and it will be a piece of stationary art untill they put me in the ground!

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On 5/31/2018 at 12:52 AM, Tinindian said:

Patience, patience, patience.

I have stayed away long enough from the 25 Buick to calm down and gathered enough patience to take another look at it .I removed the carb and cleaned it and blew out all of the ports.There was some trash in the fuel bowl under the seat.I also found that the needle was not attatched to the float arm which was likely why the fuel wasn't shutting off.I also cleaned the regulator and readjusted it also.When I turned on the switch the carb filled right up and shut off like it is supposed to.The engine cranked right up but started running like crap.I have the plugs gapped at 040 like everyone on this site was doing years ago.I have a set of Bob's plug wires that are pretty discolored and are possibly oil soaked.I also noticed a small chip on the dist cap close to where the hold down clip snaps on.Points are properly gapped and seam to have decent spark.I am thinking of ordering all of the ignition parts replacing everything new.

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