L72 won't idle when warm.

[Mike R.]

So, I just got my barn find L72 back (full engine rebuild with all original accessories rebuilt). The thing runs good when cold, but as it warms up, it won't idle, and is hard/impossible to restart when it dies. It even popped back through the carb (which was Rebuilt and Bench Tested by AEP). Thoughts? I was thinking possible vapor lock, but surprised it would happen while driving... After months of anticipation, I'm pretty disappointed it's not drivable...

Thanks,

Mike

[Mike R.]

Re: L72 won't idle when warm.

Should I dump the Original Carb for a modern one?

[Richard M.]

Re: L72 won't idle when warm.

Mike, Many factors possible. Describe if stock ignition and carb, etc and exactly what engine specs it was rebuilt to. This will give others more data to help diagnose. A few thoughts....

Is the choke fully open when it's hot? Maybe a vacuum leak when it gets hot?

I'd put a vacuum gauge on it and note readings when cold then warming up and then normalized at temp. Did you adjust mixture screws using a vacuum gauge at early warm up for peak vac?

If a high end shop did the carburetor rebuild did they test it?

Rich

[Timothy B.]

Re: L72 won't idle when warm.

Mike,

Try to determine if the hot idle condition is from being rich or lean. Take things one step at a time, make sure the engine tune is correct first (ignition, timing, etc.) then carburetor initial set up including emulsion screws.

What you describe could be many things.

[David P.]

Re: L72 won't idle when warm.

I have a '66 L72 and encountered exact same problem. What coil are you using and where did you get it?