y block to rich

cvicky

cvicky

Senior Member
leaned out the float still running rich
plugs are white tailpipes are black still cranks a lot when warm but will eventually start
 
For 272 with Holley 2100 or similar carburator, the idle/fuel mixture screws are located on the back of the carb near the bottom. Adjust while a vacuum guage is hooked up to manifold vacuum and engine idling. Adjust screws to obtain a reading of around 19-20 on the guage and fine tune from there. Turn clockwise to lean out. Turn counterclockwise to enrichen the mixture.
Hard starting after engine has warmed up could be a number of things (carb internal leak, flooding, bad economizer valve, faulty ignition condenser breaking down under the heat).
 
cvicky said:
leaned out the float still running rich
plugs are white tailpipes are black still cranks a lot when warm but will eventually start.
Click to expand...


Clean plugs indicated the fuel mixture is correct (or possibly lean). The black soot out of the tailpipe is most likely accumulated carbon in the exhaust system from when it was running rich.

If it is hard to start while warm, I would look at ethanol fuel evaporation/flooding.
 
I agree with KULTULZ. Once the tailpipe gets black, it takes forever to change. Don't go by the tailpipe. Go by the spark plugs. Sounds like if anything it may be on the lean side, but if it runs OK, I wouldn't worry.
Also, put the float back to factory specs. Lowering a float is not the way to lean out a carburetor. Also, not sure what year or carb you are talking about.

Sal
 
"hard to start when warm" could be worn piston rings that seal when engine is cold, but don't seal when warm,.,a cylinder compression check is in order.
 
If the no-start is found not to be fuel delivery caused, yes, a compression and leak-down test with a starter draw test.
 
Does it tend to start as you relax the key from the start position? If so that could indicate electrical related...
 
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