Dampfmaschine

Hello all, I'm new on this forum so I hope I'm following proper protocol by posting this issue on this particular thread.

First of, I have a 1985 Chevrolet C10 with a Goodwrench 350 that has stock internals. Around July I installed a remanufactured Edelbrock 1406 to replace the original carb. I had to use an Edelbrock manifold adapter plate so everything would mount up correctly. The carburetor comes from a reputable source, National Carburetors. I also have two fuel filters. One before the fuel pump and one before the carburetor. Since then it has run without any problems until recently. When I start up the truck cold, I pump the throttle once to give it a shot of fuel and set the choke. It'll start up and run fine until I tap the throttle to release the choke. Then, when it's idling off choke, it'll slowly start to sputter then die out. Then a small amount of fuel drips from the right side (from driver's view) of the carburetor. What's more is everything off idle is just fine. I can run WOT, cruise, and accelerate without any problems. it's at idle that I have the problem.

Some possible explanations I've thought up is, 1) Fuel pressure to high. I'm going to replace the fuel filter before the carburetor with a fuel pressure gauge to make sure I have 5 psi to the inlet. 2) Plugged bowl inlet. Perhaps the float is not able to seat properly, resulting in a flooded engine at idle. If the pressure is satisfactory, I plan on splitting the carburetor to examine and clean the fuel bowl inlet and check the float height to 7/16". 3) manifold vacuum leak. I might also check the area between the carburetor and manifold for leaks. I read that one can spray starting fluid around that area and if there is a sudden, momentary increase in RPM, you have an indication of a manifold leak.

I know this a lot to read. I appreciate the patience and any insight.

kevinkpk

The choke plate isn't set correct.

Dampfmaschine

What kind of adjustment would you recommend?

Dampfmaschine

I'll also add that the choke is wide open after I tap the throttle. The primaries seem to have a clear, unobstructed opening.

kevinkpk

Choke plate cold should be full closed. If you have fuel running out of the carb top, it's a float issue. I check floats with holding them under a pail of water, if it floats, it's good. Setting the float drop, I do by hand, there is a scale you set it by from float tip to top of carb plate with gasket. If this is a hot air choke, it should remain closed until the choke spring heats up, and raises the arm to open the choke plate.

Dampfmaschine

I tried adjusting the electric choke with the three screws on the side. Same results. I now plan to split the carburetor in half and check float height along with making sure the needle has a firm seat.

Dampfmaschine

All,
Issue is resolved. Split the carburetor to examine internals. In one float chamber needle seat, found a small piece of rubber-like material preventing the needle from fully closing the fuel off. Sprayed carb cleaner through inlets followed by shop air. Float height was just under 7/16". Adjusted it to specs. Reinstalled carb to find it had the same issue. On choke, engine idled fine. Off choke, it died. Screwed low-idle screws in to stops and backed off both 1.5 turns CCW. Adjusted until smooth idle at approximately 900 RPM was achieved.