• When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.

Carburetor running rich after rebuild

I should qualify my statement in post #59:

If the rubber diaphragm in the PV is leaking, it will affect idle.

When vac is applied to the PV, it closes the valve that is positioned between the main jets [ it is part of the PV ]. If that valve leaks, it will not affect idle but will give a rich cruise condition.
Yes, you are correct. It is a vacuum secondary. I am somewhat of a novice, and used the wrong terminology. Which gasket exactly are you describing? The one between the metering block and the main body of the carb?
Yes, but the rear. Which has no metering block.
It has a plate, and sometimes a steel shim inside the bowl.
Yes, but the rear. Which has no metering block.
It has a plate, and sometimes a steel shim inside the bowl.
I replaced the gasket I removed from between the rear fuel bowl and the body of the carb with a matching new gasket. It had the metal plate, but it did not have the steel thin shim.
Thanks to all who took the time to convey their knowledge and troubleshooting ideas. At this point, I'm going to take it apart and check everything over again, especially with respect to clear passages, proper gaskets and power valve condition. in the end, might end up purchasing a new carburetor. What would be your recommendations for a new carb. It's for a stock 1970 440 magnum.
A previous post above is correct - blue smoke is oil burn, not fuel. Rich fuel burn is usually black(ish) and as another post stated above, will burn your eyes as the engine is running. Both scenarios will cause plug fouling.
I wasn’t cautious enough about ensuring the gasket stayed in the machined recess of the PV and it seemed to tighten up OK. But it got trapped/pinched on the shoulder of the PV gasket recess causing a fuel leak. Actually it was a major fuel leak - the engine wouldn’t even fire So probably not your problem but I’ll throw it out as one remote possibility. I learned to hold the metering block horizontal and screw the PV into it from the underside so that gravity helps keep the gasket in place.
If it ran better before the rebuild, and based on what you describe after the rebuild, this would be my first guess, PV gasket misaligned. Second guess is a leaking fuel inlet needle and seat.
Best new carb would be Edel 800 AVS2......or an Edel 800 AVS2.
I have a situation that although different, may be helpful. I have a 750 brawler. Brand new it ran like absolute dog s*** out of the box and I called Holley to find out what to do with it and they let me take it apart. Thinking it was something to do with a float or needle. After taking the secondary bowl off. I found the metering plate that was installed by the factory, never torqued down 3 of the 6 screws! It leaked like crazy directly into the intake, and was a factory problem! But I was able to fix it, all the adjustments in the world would never fix this, but it was a brand new carb I didn't want to take apart. Runs like a scalded dog now. Totally adjustable just like it was designed. I was lucky to find the "smoking gun".

Auto Transport Service