TR2/3/3A Hot Idle Problem [TR3A]

[JohnnyMead]

After my TR3A has been driven for 30 minutes or so in hot weather the idle speed will slowly drop from 1,000 RPM to a point where the engine will stall (maybe after a minute). It always starts right up after this happens. Careful ignition and carb tuning has never cured this annoying little habit.
Engine runs well otherwise.
Suggestions appreciated!

John
1960 TR3A
Carbondale, IL

 

[TomMull]

John,
Idle slowing in very hot weather is, in my experience, fairly normal and I would normally crank up the idle speed a bit. But you are already running quite fast at 1000 rpm. (I assume engine is stock). Therefore, I'd look closely at the carbs, particularity the pistons. Make sure they are absolutely free in the bores and that the needles are straight.
Tom

 

[TR3driver]

My idle was a lot more repeatable after I figured out that the throttle plate in the front carb was not properly centered with the idle stop arm up against the carb body. The shaft has to actually move just a bit to the rear to let the plate close fully.

But I agree with Tom, check that the pistons drop freely and land with a distinct click. Another thing to try would be going about 1/2 flat leaner on mixture.

 

[JohnnyMead]

Thanks guys. I'll try those suggestions under hot engine conditions.

 

[JohnnyMead]

Re: Hot Idle Problem [TR3A] - Results

Leaning the carburetors by one flat has helped the hot idle stall issue.
Thanks again.
John