63 Riv carb- idiot owner?

[Zimm63]

After years of fooling with old cars, I am having an idiot attack.  I just cannot seem to get the AFB in my Riv working properly.  

 

Symptom is gas leaking out of the carb when running.  Gas is pouring out the jets at idle as well as every other point that the thing can leak.  Sunk float, stuck float, bad valve?  Dunno.  Fixed all that with a kit from the Carb Shop.  Best out there.  Original carb had this problem.  Spare carb did the same thing.  Rebuilt the spare with the good kit and things were fine for a while.  Car ran great Saturday a week ago.  Today, gas all over the place.  Filter is new, gas line is new from filter to carb.

 

Obviously, I am the problem.  

 

Can anyone refer me to a car shop that knows what they are doing?  

 

 

[KongaMan]

Fuel pressure?

[Zimm63]

Stock pump.  Not new.  How/why would it jump up the pressure?  

[pyntre]

Fuel pressure !!! Is the fuel pump new ? I was told these carbs like ,or only need , 4-5 lbs of fuel pressure . The new fuel pumps are putting out too much for theses old carbs , I may put a regulator on mine as much as I hate to ....

Edited April 2, 2018 by pyntre (see edit history)

[telriv]

Install a pressure gauge to find out BEFORE replacing ANY parts. Could be carb. is boiling over from too much heat. Heat riser stuck closed???

NO stainless plate under carb??? Engine overheating??? Install temporary mechanical temp gauge. Float levels too High??? Were floats replaced???

Can be MANY things causing problems.

[60FlatTop]

The stock pump self-regulates. Backpressure from the closed needle valve keeps the diaphragm from pumping even though the rocker arm in the pump keeps rocking. No regulator should ever be needed. Maybe the arm on your pump diaphragm is stuck or damaged. If you have a replacement pump with a pressed body, toss it and try a new one. If you still have an original style pump that is screwed together get a kit and rebuild it. That would be my plan.

Bernie

[Seafoam65]

We've had trouble in my shop from replacement pumps putting out 12 psi of pressure, overwhelming the needle and seat.

Never saw this problem till about 7 years ago, now we see it all the time. The problem is that there is only one manufacturer

making pumps for a lot of the old engines regardless of the name on the box. I've had to resort to using fuel pressure regulators

on a couple of cars that I couldn't get any other brand of pump for.  

[pyntre]

That’s what I was told also Sir Seafoam , I am working on a regulator for mine ...  

[Zimm63]

Engine not hot, plate in place, proper gaskets on the intake manifold.   Floats were good and I am confident they are properly set.  

 

The pump was replaced in 2001 or so.  Could be the issue.  I have a new one on order.  Need to see how I can rig my pressure gauge up to measure.  The one I have is set up for an old Volvo fuel injection system.  

 

Might be a few days before I can get to it.  

[60FlatTop]

I have an old pressure regulator somewhere in one of the drawers of miscellaneous parts. I removed it from the line between the vacuum tank and the carburetor on a 1932 Hudson Greater Eight. I guess it seemed like the thing to do at the time.

[lrlforfun]

OK Zimm: Several things here.  DIAGNOSE. First procedure?  Isolate your problem. 

 

1. I would start with the fuel tank. Many times there is dirt and ca ca from years of rust and corrosion.  Make sure it's clean clean.  Next, blow out all lines from the sending unit to the fuel pump. Visibly check for bum rubber hoses and it's always a good idea to install fresh hoses and clamps. 

 

2. Because it's only $20 or so I'd recommend a fresh fuel pump too. Easy to install; with a pair of  9/16 bolts. A/c makes it a wee bit trickier but still, no big deal. 

 

3. Replace the fuel filter and hoses and clamps from the fuel pump to the carb.

 

4. NOW......you can work on the carb.  from what you mentioned it's sounds like it's getting fresh contamination.. DIAGNOSE. Needle and seats?  Correct, free in the correct position? Floats? Upside down or not? Taking on gas?  Are they adjusted correctly?  Linkage correct? You mentioned this carb and others were kitted. perhaps a similar mistake in installation was made.  

 

 

I'm gonna put my hunch on a dirty tank,  BUT.....YOU MUST DIAGNOSE. I know because I've chased my tail 103 times and finally got it right!

 

 

Good luck, Mitch

Edited April 3, 2018 by lrlforfun (see edit history)

[carbking]

Zimm - as others have mentioned, you need to determine the problem before throwing more money at the problem.

 

Since you checked the floats, and the fuel pump is over 15 years old, I also am going to vote for dirt. When removing the lines, you will disturb some residue in the lines which will move forward with the fuel into the carburetor (unless you also replaced all the lines). The issue MAY solve itself, and it may not. I would begin by cleaning up all of the fuel on the manifold, and completely drying both manifold and carburetor. Then, with a couple of helpers (have one crank the engine, while you and the other stare at the carburetor from opposite sides of the vehicle) to determine exactly from where the fuel is coming.

 

Please read this link:  http://www.thecarburetorshop.com/Troubleshooting.htm#Fuelleak

 

We need to know if the fuel is coming out when you shut the engine off; or if when you try to start.

 

My telephone hours are 9-4 Mon-Tues central time. Will be happy to try to help.

 

Jon.

[Zimm63]

As stated previously, it will be a couple days before I can get back to this.  

 

More info:  Fuel filter is new, line from filter to carb is new.  I opened the old filter and there was no significant dirt in it.  Tank was out of the car and cleaned a few years back and new rubber lines installed at that time.  Gas is coming out othe main jets when looking down the carb.  It also is leaking out of the top of the accelerator pump.   Car blubbers due to excessive fuel.  Fortunately, it hasn't backfired and set the thing on fire.  I will keep an extinguisher handy.  I have a couple that are the replacement for Halon.  Really wouldn't want to use a dry powder one unless I had to.  

 

Immediate plan is to T in a fuel pressure gauge betweeen the filter and the carb.  Excess pressure makes sense, but I have never seen a fuel pump fail that way.  My normal is they fail to no pressure.  The fact that it has done it with two carbs and after a rebuild appears to be a clue.  I may be dense, but I do get there after a while.

 

More as information developed.

 

 

[Bloo]

3 hours ago, Zimm63 said:

 

Immediate plan is to T in a fuel pressure gauge betweeen the filter and the carb.

 

Good plan. Also, lots of good information already in this thread.

 

If you are short on room, and have an inline filter, you can get a fuel filter with a third port for a return line. I think Buick had one like that in the 60s, but I use a Chrysler K-car one (80-84-ish 2.2 Liter with carburetor) as it is smaller. The third port has an orifice in it that I have drilled out. You might not have to drill it for this duty, but I would. It removes one detail to wonder about. The third port is smaller, and perfect for temporarily hooking up a gauge. Most automotive vacuum gauges have a fuel pressure scale that is right for carbureted cars. Thats what I use.

 

On some GM cars that have a solid piece of metal line all the way from the fuel pump to the carb, I have resorted to just disconnecting or removing the stock line, and temporarily hooking up with brass fittings and hose.

 

Don't get too hung up on exact pressure. If it is pretty close, its fine. There is going to be some variation as the float valve opens and closes. You will get to see what it looks like pumping, and what it looks like with the valve closed.

 

As others have mentioned, pressure is controlled by the internal diaphragm spring in the pump. It just sits there pushing against the float valve. When the float valve is closed, the diaphragm just stays up, and the arm does nothing. As fuel flows into the carb when the float valve opens, the diaphragm comes back down and contacts the arm, and pumping resumes.

 

You can only compensate so much for high fuel pressure by lowering the float level. A very slight change might be ok. I have also heard of people having to lower the float level slightly to compensate for the different specific gravity of today's alcohol-laced fuel. I have not had to do that yet, but I am not ruling it out.

 

Don't add a regulator unless forced. If the fuel pump is the problem, fix, replace, or find some way to make it work as designed. Regulators, especially cheap ones, are the road to madness.

 

 

[petelempert]

I had the same problem. Dirt. I'm agreeing with the posts above. Makes the jets and floats stick. Easy test...Try rigging up a fuel line to a jerry can of gas. Disconnect all fuel lines from the carb. Blow out the carb with air and carb cleaner. Hook the carb up to the jerry can. Put the jerry can up high so gravity pushes fuel to the carb. Let it run for a while. In my case, it ran great like this. As soon as I hooked back up to the conventional lines, it ran like crap. I also had the thought provoking fuel fountain spilling gas all over the engine. No smoking please. Worked for me. Worth a try. PRL

[KongaMan]

42 minutes ago, petelempert said:

I had the same problem. Dirt. I'm agreeing with the posts above. Makes the jets and floats stick. Easy test...Try rigging up a fuel line to a jerry can of gas. Disconnect all fuel lines from the carb. Blow out the carb with air and carb cleaner. Hook the carb up to the jerry can. Put the jerry can up high so gravity pushes fuel to the carb. Let it run for a while. In my case, it ran great like this. As soon as I hooked back up to the conventional lines, it ran like crap. I also had the thought provoking fuel fountain spilling gas all over the engine. No smoking please. Worked for me. Worth a try. PRL

Might want to also plug the fuel line from the pump.

[Zimm63]

Had a few minutes today to conduct some experiments.    

 

Fuel pressure gauge reads 4-5 psi pumping against a plugged line, disconnected from the carb using the starter.  Hooked it up to the carb and it read 4-5 with the engine running.  Ran less than a minute before leaking started out of the top of the accelerator pump.  

 

So, dirt or floats set too high?  If floats too high, why didn't it leak immediately after the rebuild?  If dirt, how is it getting through the brand new filter and line between the pump and carb.  The floats looked good when I rebuilt the carb last fall.  

 

Are there any good shops out there who can rebuild this thing to eliminate any question of it being done properly?   

 

Back to tax work for me.  10 days to go.

 

[Bloo]

Floats are too high or a float valve is bad. Are they rubber tipped or steel? The steel ones often had trouble like this, though I understand people prefer them today for use with ethanol.

 

Sink your floats in hot water and look for bubbles. Still ok? Put them back on and recheck float height and float drop. Didnt have to set? While the top plate is still off, blow through fuel inlet, and slowly turn the top plate over. The valves should shut off completely. Go slow so the floats dont drop suddenly and "pound" the valve shut when it might not shut tightly otherwise.

 

Other thoughts: Does this carb use wire clips from the float valve needle to the float and are they in place? There are 2 float valves, do both of them run over or just the accelerator pump side?. You mentioned running out the top of the accelerator pump. Fuel would be running out the main discharge tubes down in the throats before the fuel gets high enough to come out the accelerator pump, and you should be able to see this in the secondaries, even if the choke is closed on the primaries and you cant see in.

Edited April 7, 2018 by Bloo (see edit history)

[KongaMan]

If the same thing happened with three different carbs, maybe it isn't the carb.  OTOH, if all three carbs have been rebuilt, maybe there's a common error in the rebuilding process.

 

As suggested earlier, check that the float valves close.  You might also check that with the air horn right side up: lift the floats to proper height to see if they close.  Suggestion: hold air horn upright, hold a 7/32" drill against the gasket, then lift the floats until they hit the drill.  Did the valves close?

[1965rivgs]

6 hours ago, Zimm63 said:

Had a few minutes today to conduct some experiments.    

 

Fuel pressure gauge reads 4-5 psi pumping against a plugged line, disconnected from the carb using the starter.  Hooked it up to the carb and it read 4-5 with the engine running.  Ran less than a minute before leaking started out of the top of the accelerator pump.  

 

So, dirt or floats set too high?  If floats too high, why didn't it leak immediately after the rebuild?  If dirt, how is it getting through the brand new filter and line between the pump and carb.  The floats looked good when I rebuilt the carb last fall.  

 

Are there any good shops out there who can rebuild this thing to eliminate any question of it being done properly?   

 

Back to tax work for me.  10 days to go.

 

Remove the floats right after you experience the flooding and shake them. If you have a float filling with fuel you should be able to hear and feel the liquid fuel sloshing about in the float. Sometimes it takes some running time for the floats to take on enough fuel to display the symptoms.

  Tom Mooney

[Zimm63]

Following up on this topic.  

 

Tax season being over and the sun shining, I dug into this today.  Pulled the top off the carb and had a look see.  I tried the blow through test and a valve was leaking.  Hot water test on the floats showed both were good.  

 

SOB!!  There was dirt in the valve.  I am guessing that I did a poor job of cleaning out the passages when I put the kit in it a few months back.  I pulled the valves out, found more dirt, sprayed a bunch of cleaner through it, then blew it out.  You will recall that I installed a new filter and line when the carb went back on the engine.  I doubt any dirt got through that. 

 

All back together now and it seems to run like before.  Now I can start tracking down that bit of a miss I feel at speed.  

 

Anybody got suggestions as how best to clean the internal passages?  I still want to rebuild the original carb and put it back on.  I have a new kit from the Carb Shop ready to go.  

 

 

[telriv]

If the carb. is an AFB I have been rebuilding/re-bushing them for yrs. & have done MANY users of this site. After the rebuild I install it on a '64 Riv. I have & drive it BEFORE sending it back to make ABSOLUTELY SURE there are no problems.

 

 

Tom T.

 

 

 

[Zimm63]

PM sent.  Yes, its an AFB.