Got a question for everyone. I have a 60 Caddy with a 390, it won't run correctly. At times I can get it to idle somewhat ok but won't stay running. It seems to flood itself out and quits. There will be gas gurgling and fuming out the top and then won't start for a while until it cools off. It seems to be getting so hot that the gas is boiling inside the carb, at least that is what it sounds like. This is what I have tried so far, I took the carb apart and cleaned it out, I did not pull the jets or anything. I did check the floats according to the manual and they were ok and not sticking. There did not seem to be any debris in the bowls so I did not mess with anything internal. I changed the fuel filter, drained the gas from the tank and put fresh gas in. It has a new fuel pump and that seems to be working fine, I unhooked the hose and cranked it over pumping fuel into a bucket. I also changed the intake manifold a week ago, the old one had a crack in the mounting flange and would not seal. It has new plugs and wires and a pertronics conversion last fall. It will idle when it first starts but when it is warmed up and the choke is off it starts acting up. it seems like it is getting too much gas or something. I am not sure why it seems to be getting hot like it is or is this normal? I don't know what to try next, please help because I am running short on hair from pulling it out!
try a fuel pressure regulator, my carb would overflow until i used a regulator. Also did you change the intake gaskets? my '62 would fire but wouldn't stay running because the gaskets were bad and were letting air in
I've had the same thing happen to me on several cars. Some had floats sticking and one had too much fuel pressure from a Holley fuel pump
Is the heatriser on the exhaust manifold free to move and working? If it is stuck closed most all the exhaust gas is going through the intake manifold under the carb overheating it,thus boiling the fuel.
Could also be the fuel line from the pump to the carb is too close to the intake, or other heat source, causing vapor lock and, or percolation. You might also try a heat dissipating type thick gasket under the carb to lower the fuel temp in the fuel bowls.
There should probably be a Phenolic or fiber spacer under the carb about a half inch thick. Just a thought, have you actually checked the carb temperature? It would have to be pretty warm to be boiling the gas. Possible stuck heat riser. Although you may not have a sticking float, you may have a sinking one. Take it out and shake it to see if it has fluid in it. No more than 6 psi pressure If you running an AFB. Any one else?
In addition to the spacer my 63 shop manual points out that the carb must have the thin metal heat shield below the carb or it will not idle.
check your fuel lines from your tank all the ways to your carb for cracks. extra air in your fuel line to your carb will make it run like you have a miss. also run a carb spacer.
That is what I was wondering also, I am going to get a regulator and try that. I did change the gasket when I put the new intake on.
i think the guys that talked about the thin metal heat shield below the carb hit the nail on the head,,,,my 41 caddy had a 390 in it, and i had the same exact problem,,,,that's what fixed it,,,,it's amazing how a little thin piece of metal can make such a huge difference.......
Forgot to mention it is an Edlebrock 600cfm w/ electric choke. The carb is damn hot when this happens. The floats did not have any fluid in them when I checked them but I will check again.
I think I still have the phenolic spacer but it did not have the heat shield when I got the car. I will have to track one down. Thanks to everyone for thier insight. I willo try these see if it cures the problem
Did it run before you changed the manifold? You said the old one would not seal, was it a va***e leak or coolant leak?
It ran good before, it was a vacuum leak. That is what is making me so mad, it ran fine when the intake and exhaust manifolds were leaking but now everything is sealed up right and it won't run for ****!
if it ran good with a vacuum leak, it was getting some unaccounted for air. & tuned for that? new manifold - is cold start/warm up rich? Give it a vacuum leak by pulling a hose and see if that changes anything? When ever a new problem shows up, go back to the last thing you did and start there
I prefer the original carter to the edelbrock remake, it's not hardly the same. Oh and push come to shove, I had a '62 and still have an orphan original carter in original shape....
I didnt see any tips on the vacuum issues. To trouble shoot the vacuum leaks you can use WD40 and spray it on the point of contact of manifolds and carburators, where the two bolt together. Just use it sparingly so not to cause a flamability issue. The motor will change rpms if you hit the spot. Also when the motor runs decent peek into the venturies in the carb, you should not see fuel drip while idleing, if you do the float is misadjusted or there is something in the needle and seat.
Right from inside the car or right as you are looing at the front of the carb? I have it on the right as in from inside the car.
so you removed the heat riser, but what of plugging the idle port heat p***ages in the new manifold? still circulating some exhaust under the carb otherwise?
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