Engine Dieseling...how can i stop it???
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Engine Dieseling...how can i stop it???
75f250...400 ..complete rebuild.....cpr..probably...9.3 or so to one. Question???It seems tHAT THE ENGINE KEEPS GOING ABOUT 90% of the time, after i turn the key off. It runs absolutely great. I alternate one tank 89 oct. , then 93 oct. I have been either poping the clutch to kill it or just turning off the electric fuel pump. Any suggestions??? , thanks , fd
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From: Northern Va
Engine Dieseling...how can i stop it???
Once the ignition is turned off, the timing wouldn't factor in because there should be more spark to be timed.
Most often run on is caused by the idle being too high, or carbon build-up in the combustion chamber causing a little glowing ember the ignites the fuel.
Most often run on is caused by the idle being too high, or carbon build-up in the combustion chamber causing a little glowing ember the ignites the fuel.
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Engine Dieseling...how can i stop it???
Mr Fatdaddy, the stock setup has an idle solenoid on the carb linkage. The solenoid controls the idle, and when the key is turned off, the solenoid allows the throttle linkage to retract, and then the throttle plate closes completely.
Since the air/fuel is immediately cut off, the possibility of run-on is eliminated.
All of the previous posters are correct, in that the run-on is enabled by the throttle plates being to far opened at idle. But this is corrected if you advance the initial timing. If you advance the initial timing, you will also have to reduce the idle speed. (More advanced timing equals faster idle rpm) This in turn closes the throttle plates more, and reduces the chance of run-on.
Since the air/fuel is immediately cut off, the possibility of run-on is eliminated.
All of the previous posters are correct, in that the run-on is enabled by the throttle plates being to far opened at idle. But this is corrected if you advance the initial timing. If you advance the initial timing, you will also have to reduce the idle speed. (More advanced timing equals faster idle rpm) This in turn closes the throttle plates more, and reduces the chance of run-on.
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Engine Dieseling...how can i stop it???
I want to thank each of you'll for your input and diagnosis. Not being an experienced carbourator repair person I'm in the learning phase and all knowledgeable help is appreciated. I think i need to find an old carb that will fit on my engine and just do a complete rebuild then I'll understand a lot more than i do now. fd 
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Engine Dieseling...how can i stop it???
Do you have a tach? Know what the idle speed actually is?
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Engine Dieseling...how can i stop it???
Yes...i've got a tach, but, it reads about half of the real RPM. when we went thru the engine i (we) put in a complete MSD system. Msd-6a box , dizzy and coil. For some reason the msd 6a is not sending a correct signal to the tach and it has never read correctly. I should call them in El Paso and see if there is a fix . I just never really needed the tach till now. Things like brakes and lights seemed more important. will try to call them before the end of the week . thanks for your help , fd
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