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I need your help - Carb leaks / engine dies
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Chrome58
Posted 2019-05-04 2:08 PM (#581764)
Subject: I need your help - Carb leaks / engine dies



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Guys, I need your help.
I'm fed up. I can't even enjoy my car without a great amount of stress.

It happened several times : the engine suddenly dies on me, either at idle at a red light, or even at low rpm. It usually happens after 10-15 minutes after the first startup.
There's a strong odor of gas in the engine compartment, and I can see gas dripping at the linkage, making puddles on the intake.

For it to start again, I need to wait about 15 minutes and then try several time with my foot pushing hard on the accelerator pedal.
She then starts with some smoke but it does not last long, the engine may die again a minute later.
To return to a normal situation, I need to wait several hours ...

Now for some technical data :
- 1958 poly 318 engine, originally a 2-bbl setup
- 2 x 4 bbl WCFB setup
- hotter camshaft (provided by Gary Pavlovich) to suit the 2 x 4 bbl WCFB setup
- the carbs were rebuilt professionally when I bought them several years ago
- after it happened to me the first time, I bought a full kit and rebuilt again the primary carb last year (but it happened again)
- the automatic mechanical choke was replaced by an electrical one (not sure it's properly adjusted I might add)
- my spark plugs were Champion RJ12, I replaced them with RJ14 (happened with both types). The RJ12 were blackened so it means I'm running too rich.

I don't know where to start and what to do.
I'm really fed up because I cannot take my car for a drive and enjoy it.

At first I thought it might have been a case of "vapor lock" because I had (on top of everything else) an overheating problem.
That overheating problem is solved now, but it's still happening.

Thanks for your help.
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1960fury
Posted 2019-05-04 4:08 PM (#581770 - in reply to #581764)
Subject: RE: I need your help - Carb leaks / engine dies



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Chrome58 - 2019-05-04 2:08 PM


There's a strong odor of gas in the engine compartment, and I can see gas dripping at the linkage, making puddles on the intake.

For it to start again, I need to wait about 15 minutes and then try several time with my foot pushing hard on the accelerator pedal.
She then starts with some smoke but it does not last long, the engine may die again a minute later.


You mean you got a leaking/dripping carb that causes puddles of gasoline on the intake and you realy start it again? I'm not sure what to say/think about that................

Edited by 1960fury 2019-05-04 4:09 PM
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wizard
Posted 2019-05-04 4:15 PM (#581771 - in reply to #581764)
Subject: Re: I need your help - Carb leaks / engine dies



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Many plausible reasons, but wrong adjusted floats and/or needle/seat that don't like modern fuel (old car kit)
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Chrome58
Posted 2019-05-04 4:40 PM (#581773 - in reply to #581771)
Subject: Re: I need your help - Carb leaks / engine dies



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1960fury - 2019-05-04 10:08 PM

You mean you got a leaking/dripping carb that causes puddles of gasoline on the intake and you realy start it again? I'm not sure what to say/think about that................

That really helps. Thank you ............

wizard - 2019-05-04 10:15 PM

Many plausible reasons, but wrong adjusted floats and/or needle/seat that don't like modern fuel (old car kit)

The kit I bought and used was a modern one.
But I don't know if that's what you mean.
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1960fury
Posted 2019-05-04 5:43 PM (#581778 - in reply to #581773)
Subject: Re: I need your help - Carb leaks / engine dies



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Chrome58 - 2019-05-04 4:40 PM

1960fury - 2019-05-04 10:08 PM

You mean you got a leaking/dripping carb that causes puddles of gasoline on the intake and you realy start it again? I'm not sure what to say/think about that................

That really helps. Thank you ............



So you expected us to detect the leak in your fuel system via the internet based on "I can see gas dripping on the intake"? I see.

Yes, it should help you as it was supposed to make you THINK. If you run your car with a carb that is leaking puddles on the engine, you must be out of your mind or want to collect insurance money at the expense of a classic car.

What about not firing it up (literally) but disconnecting the battery instead immediately?

This happened last week 2 miles away from me to a new Porsche, supposedly a fuel leak. The owner got insured trying to save its belongings in the car:

https://celleheute.de/porsche-cabrio-faellt-flammen-zum-opfer/

Edited by 1960fury 2019-05-04 5:55 PM
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1960fury
Posted 2019-05-04 6:01 PM (#581779 - in reply to #581764)
Subject: Re: I need your help - Carb leaks / engine dies



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As it affected engine operation, it was likely what Wiz said, a leaking inlet valve or incorrect adjusted or leaking floats. Anyway, do not run an engine with a leaking/flooding carb, even if its only leaking into the engine.
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wizard
Posted 2019-05-05 2:54 AM (#581794 - in reply to #581764)
Subject: Re: I need your help - Carb leaks / engine dies



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Is the fuel pump a standard mechanical one, or an electric one?

If electric, it might have too high pressure
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Chrome58
Posted 2019-05-05 5:30 AM (#581796 - in reply to #581764)
Subject: Re: I need your help - Carb leaks / engine dies



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Standard mechanical one.
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Powerflite
Posted 2019-05-05 9:38 AM (#581800 - in reply to #581764)
Subject: Re: I need your help - Carb leaks / engine dies



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Your symptoms are coming from the carb dripping fuel into your intake. It is flooding it while sitting and making it run rich while running. If you continue to drive it like this, it will dump a lot of fuel into your oil (while the car is off) and could cause bearing issues eventually. I had something similar happen to my Coronet. So once you get it fixed, check & change your oil too. It sounds like the leak is from the inside of the carb, probably coming out at the throttle rod. Is that correct? If so, I agree with Wizard that either your float is not adjusted properly, or it is sunk - meaning it has a leak in the float causing it to always be low. Take the float out and submerge it in hot water and look for bubbles. This is the most likely cause, but a bad or bent needle/seat could also be the problem.
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Chrome58
Posted 2019-05-05 12:04 PM (#581807 - in reply to #581796)
Subject: Re: I need your help - Carb leaks / engine dies



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I checked the floats for leaks and they're leak proof.
And the kit I used to rebuilt the carb last year was ethanol ready.

I may (or may not) have found something at the floats adjustment.

Do the floats have to clear the minimal height on their whole length or is it just at a specific points ?

The FSM states that "Both floats shoud just clear horizontal part of gauge".
But the pictures mentions that they should just touch at certain points (see pic).
If the floats have indeed to clear the minimal height on their whole length, then they are wrongly adjusted.
They're too high, which might provoke the flooding.

PS : I found out that I have 2631/2632 carbs (1957) whereas I should have 2761/2762 (1958).
PS2 : I ordered on eBay the 2 CARTER tools necessary to check the float adjustment on primaries (7/32") and secondaries (11/32").

Edited by Chrome58 2019-05-05 12:12 PM




(Floats.jpg)



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Attachments Floats.jpg (104KB - 11 downloads)
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wizard
Posted 2019-05-05 1:45 PM (#581818 - in reply to #581764)
Subject: Re: I need your help - Carb leaks / engine dies



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Vincent, the primary float level measure shall be touching only on the edge as shown in Fig 75
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ronbo97
Posted 2019-05-05 11:06 PM (#581849 - in reply to #581818)
Subject: Re: I need your help - Carb leaks / engine dies


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Vincent - There are two float settings: float level and float drop. Both have to be dead on or you will have problems.

Ron

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Chrome58
Posted 2019-05-06 5:33 AM (#581856 - in reply to #581849)
Subject: Re: I need your help - Carb leaks / engine dies



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wizard - 2019-05-05 7:45 PM

Vincent, the primary float level measure shall be touching only on the edge as shown in Fig 75

OK thanks Sven.

ronbo97 - 2019-05-06 5:06 AM

Vincent - There are two float settings: float level and float drop. Both have to be dead on or you will have problems.


Yes I know Ron, and I'm going to check it also, but a wrong float drop is less likely to be responsible for flooding the carb, if I'm not mistaken.

Anyway, carb flooding can only be caused by 3 things :
- the gas pump (too much pressure)
- the floats (adjustment, leak or stuck) : they're leak proof, but do need adjustment
- the valves (adjustment or stuck) : new valves ("Daytona" style) were fitted last year, and everything is still in place

In order to check for gas pump pressure, I'm going to make a test with the carb as it is, and feed it with gas coming from a can by gravity.
If the carb does not leak when both tanks are full, then the pump pressure might be the culprit.


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ronbo97
Posted 2019-05-06 2:06 PM (#581867 - in reply to #581856)
Subject: Re: I need your help - Carb leaks / engine dies


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Chrome58 - 2019-05-06 5:33 AM  In order to check for gas pump pressure, I'm going to make a test with the carb as it is, and feed it with gas coming from a can by gravity. If the carb does not leak when both tanks are full, then the pump pressure might be the culprit.

The correct way to check fuel pump pressure is with a pressure gauge. You attach rubber fuel line to the output port on the fuel pump. Then attach the gauge to that end. Pull the distributor to coil wire so the car won't start. Then have an assistant crank the engine for about 5 seconds. The gauge will register the pressure. Note: Pressure should be 7 pounds maximum. If it's more than 10% higher, you have a problem. 

Ron

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Chrome58
Posted 2019-05-06 3:00 PM (#581868 - in reply to #581764)
Subject: Re: I need your help - Carb leaks / engine dies



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Thanks Ron, I'll try to do that.
I'll have to find a pressure gauge.

I just thought about something : the OEM 2x4 fuel line goes from the pump to a glass bowl filter, and then to the carburetors.
As I have a fuel filter before the pump (which I think is safer anyway), I did NOT put that glass bowl filter.
But that means that there's a drop of pressure missing from the line, which should be generated by that filter.


Edited by Chrome58 2019-05-06 3:09 PM




(bowl.jpg)



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Attachments bowl.jpg (235KB - 12 downloads)
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Powerflite
Posted 2019-05-06 4:00 PM (#581871 - in reply to #581764)
Subject: Re: I need your help - Carb leaks / engine dies



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I don't run the filter at all, with just a paper filter before the pump and I don't have issues like yours on my Dodge.
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1960fury
Posted 2019-05-06 4:08 PM (#581872 - in reply to #581764)
Subject: Re: I need your help - Carb leaks / engine dies



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The only filter I run is the OE Nylon one in the tank. Never had any issues. Of course the Holleys have a fine metal screen in the inlets but I never found anything in there.
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ronbo97
Posted 2019-05-06 6:56 PM (#581880 - in reply to #581872)
Subject: Re: I need your help - Carb leaks / engine dies


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So you have the glass bowl filter at the carb, but no filter inside the bowl ? That's just silly.

But either way, it should not affect fuel pump pressure. Buy a gauge and test at the pump. Let us know.

Ron

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Chrome58
Posted 2019-05-07 12:49 AM (#581888 - in reply to #581880)
Subject: Re: I need your help - Carb leaks / engine dies



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ronbo97 - 2019-05-07 12:56 AM

So you have the glass bowl filter at the carb, but no filter inside the bowl ? That's just silly.

No Ron, you misunderstood : I meant I have no glass bowl filter at all.

But either way, it should not affect fuel pump pressure.
Buy a gauge and test at the pump. Let us know.

I'm indeed buying a pressure gauge and making the test.

Edited by Chrome58 2019-05-07 12:53 AM
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ronbo97
Posted 2019-05-07 5:06 PM (#581906 - in reply to #581888)
Subject: Re: I need your help - Carb leaks / engine dies


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It would be a good idea to install one. Some added benefits to having one are that you can see it fill (or not fill) as you crank the engine. Also, it lets you see if sediment is getting into the fuel lines and into the carb.

Ron

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Chrome58
Posted 2019-05-08 11:07 AM (#581936 - in reply to #581764)
Subject: Re: I need your help - Carb leaks / engine dies



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I do have one glass bowl filter lying around, but it came from the original 2-bbl setup.
Was it the same that was used on the 2x4 setup ?
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ronbo97
Posted 2019-05-08 4:18 PM (#581946 - in reply to #581936)
Subject: Re: I need your help - Carb leaks / engine dies


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Yes. They are all the same. 

But that's further down the road. Focus on the current problem for now.

Ron

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wizard
Posted 2019-05-08 4:36 PM (#581947 - in reply to #581946)
Subject: Re: I need your help - Carb leaks / engine dies



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ronbo97 - 2019-05-08 10:18 PM

Yes. They are all the same. 

But that's further down the road. Focus on the current problem for now.

Ron

 



That's what I thought as well Ron, and it's usually the best method to pinpoint a problem to just do one thing a the time for to not confuse and complicate the trubleshooting. But the problem might be foregin particles in the fuel/tank.

Installing a filter would rule out that possibility.
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Chrome58
Posted 2019-05-11 12:32 PM (#582024 - in reply to #581947)
Subject: Re: I need your help - Carb leaks / engine dies



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Well, it's not the pressure of the pump.
I bought a tester gauge, and upon 3 different attempts, the higher pressure measured was 6.5 psi.




(pressure.JPG)



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Attachments pressure.JPG (241KB - 10 downloads)
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wizard
Posted 2019-05-11 12:47 PM (#582025 - in reply to #581764)
Subject: Re: I need your help - Carb leaks / engine dies



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Good Vincent, next step is to check the inlet nozzle valves for foregin particles and double-check the float adjustments. Then install a filter and all should be good.
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ronbo97
Posted 2019-05-11 7:59 PM (#582033 - in reply to #582025)
Subject: Re: I need your help - Carb leaks / engine dies


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Good Job, Vincent ! You will be able to diagnose and tune your engine with that tool as well.

!00% agree with Wiz as to the next steps.

Ron

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chefothefuture
Posted 2019-05-12 1:33 AM (#582049 - in reply to #581764)
Subject: Re: I need your help - Carb leaks / engine dies


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Interesting reading this thread as I just had problem with flooding dual AFBs. Fresh rebuilds. Pressure was 7psi so I put in a pressure regulator. (I think that's a temporary fix). Carbs aren't flooding inside but the body/top gaskets are wet.
Not dripping, but weeping. Changed oil but engine has developed an occasional squeak in the top end.
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Chrome58
Posted 2019-05-20 5:25 AM (#582307 - in reply to #582025)
Subject: Re: I need your help - Carb leaks / engine dies



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Allright, I made the adjustments on the floats using the CARTER tools I found on eBay.
The only thing left to do is to adjust the float drop ... BUT I'm asking myself one question.

The secondary floats on my carburetor are different than the primaries. They are smaller. And the manual show they should be the same. I checked the WCFB parts vendors, and indeed there are 2 different models. The smaller ones (which I have) should put less force on the valve (Archimede's law).

Which float model should I have ?
(beware that I have '57 WCFB so the illustration might be incorrect)


Edited by Chrome58 2019-05-20 6:08 AM




(floats_2.jpg)



(floats_3.jpg)



(tools.jpg)



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Attachments floats_2.jpg (185KB - 10 downloads)
Attachments floats_3.jpg (84KB - 9 downloads)
Attachments tools.jpg (245KB - 9 downloads)
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Chrome58
Posted 2019-05-22 2:57 PM (#582414 - in reply to #581764)
Subject: Re: I need your help - Carb leaks / engine dies



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Anyone ?
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Powerflite
Posted 2019-05-22 5:12 PM (#582422 - in reply to #581764)
Subject: Re: I need your help - Carb leaks / engine dies



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I would assume that they should be like the ones in the picture....like yours on the left side of the picture. And I agree with you that the ones on the right will remain lower than the ones on the left. Therefore, you may still be able to use them, but you may need to calibrate the others to sit lower in the carb (i.e. higher from the lid) so that they shut off at the same time.
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ttotired
Posted 2019-05-22 5:29 PM (#582427 - in reply to #581764)
Subject: Re: I need your help - Carb leaks / engine dies



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I don't think it would matter, but what might matter is, looking at your picture, it looks like the float on the left has a pin hole in the solder in the middle of it

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Chrome58
Posted 2019-06-07 2:46 PM (#583074 - in reply to #582307)
Subject: Re: I need your help - Carb leaks / engine dies



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One more question ...

It does not appear clearly on the picture, but my floats upper edges are not parallel to the carb cover (see red arrows).
And it seems to me that every illustration I've looked at show that they are parallel to the carb cover.

Does it matter ?

Edited by Chrome58 2019-06-07 2:49 PM




(floats_2b.jpg)



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Attachments floats_2b.jpg (152KB - 8 downloads)
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Chrome58
Posted 2019-06-09 8:49 AM (#583139 - in reply to #581764)
Subject: Re: I need your help - Carb leaks / engine dies



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No one ?
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wizard
Posted 2019-06-09 12:57 PM (#583154 - in reply to #581764)
Subject: Re: I need your help - Carb leaks / engine dies



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Not really Vincent, you could straighten them by bending close to the floats and then bend close to the fulcrum point. Bending close to the floats is always more risky due to breakage or leaks
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