rosseich

I have a stock '72 LT1 350 which is running rich and loads up on idle. What can I try to lean the fuel flow? It has 70 jets on primary and 73 on secondary metering block. Runs fine at speed but rough on acceleration after idling for a minute or two.

Any ideas?

tbarb

Your rich idle condition has nothing to do with the main jets inside the carburetor. By the way, do a google search and check the main jet size, someone may have changed them unless the Holley has a secondary power valve.


Make sure the engine is warm like after a drive and adjust the A/F emulsion screws on the primary metering block. If there is no change in the rich condition after this either to much of the transfer slot is showing at idle or fuel is leaking internally into the carburetor.

Make sure the throttle blade on the primary is set even with the bottom of the transfer slot and give the engine more idle air by adjusting the secondary throttle blade open a little more. This can be done by removing the secondary stop screw and turning it over and installing it from the top and then the idle can be set.

If the engine has it's stock camshaft you should be able to do this without opening the secondary blades up into the secondary transfer slot. Do not open the secondary blades into the transfer slot or the rich condition will get worse.

If the camshaft is hot rod, you may need to get extra air from somewhere else like very small holes in blades, hopefully that is not the case.

Mike Ward

Make sure the float is adjusted properly and that the needle and seat are not leaking.

BTW- your car is a C3. This is the C2 section.