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engine stalling

adamaztr6

Freshman Member
Offline
My 1971 TR6 has an intermittent stalling problem. Sometimes when coming to a stop at a traffic light the idle suddenly becomes very rough. It drops off from normal idle and will stall out if I do not hit the gas pedal several times. Usually this only lasts 10-15 seconds at which time the idle usually corrects itself. I have the stock dual- zeniths which have been rebuilt. I have already repaired several vacuum leaks and had the distributor rebuilt. I'm not sure if it is still leaking vacuum or fuel starving. Any suggestions?
 
It could be your air valve in either carb is sticking. I would take off the air filter cover and while the engine is off, gently lift up the air valve pistons. There should be some resistance going up but should return to the down position quickly. If you see a herky-jerky motion on the way down, you should inspect the diaphram and piston.
 
It does sound like a fuel problem.
Have you got the right level of oil in the carb dashpots?
I would suspect that the fuel level in one or both float bowls is incorrect.
Does it happen only when you stop on the road or does it also occur in neutral when you rev the engine and only when it's hot?
 
It only seems to occur when its hot and being driven. I really notice it when coming off the freeway when the engine has been run at high speed. If the vehicle is just parked idling it is fine.
 
Oh, and reference the dashpot oil and level. I have read several different suggestions for how much oil should be used and the grade depending on how fast you want the valve to rise. I am using the recommended carb oil right now with resistance on the stick being felt approximately 1/2" before reaching its seated position.
 
You might see if giving it just a little bit of choke returns it to normal idle. Also you might look at your plugs (or whatever else you look at) to see if your mixture is on the lean side.

Seem to have several new forum members from Arizona (wish i could take credit for that). In what area of the state are you?
 
If you're running it quite hot, you may be experiencing some vapor lock when you come to a stop and there's no additional airflow cooling the fuel at the carbs. Your water temperature can read fine and lull you into thinking that the rest of the engine temperature is fine, too. Next time, feel the carb body. It should not be hot to the touch.

Jeff Aronson
Vinalhaven, Maine
USA
 
To Geo, I live in the North Phoenix/Cave Creek area. Were you aware the Wheels of Britain car show is on March 13th? It is going to be held at Heritage Square in downtown Phoenix.

As far as I can tell the carbs are not getting too warm. I will be doing some more road testing/tuning tomorrow. Thanks to all. Regards, Adam
 
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