my `80 1500 keeps running when shut down , but only when it`s hot , not cold . timing ok , changed plugs , new carb power valve , chked low & hi fuel shut off solenoids & ok , dist cap & wires new , ????? thanks for any help . did pass smog tho !

 

You have deposits inside the head that are hot enough to ingnite the gas mixture even without a spark. Short of diassembling your motor and cleaning the combustion chamber of deposits, you are going to have to live with it. This is common with older high mileage engines.

One solution is to put the car in gear after shutting off the engine.

Another is to step on the gas pedal after turning off the engine to inject cool air and gas into the cylinder.

I had one car that keptdieseling long enough I could go into a store and come back out and it was still going.

 

there is a way to clean the pistons cylinders my friend told me this one. to put fuel system cleaner directly in tothe cylinders and crankthe engine over for a while with the spark/glow plugs removed then replace the plugs and fire it up. it will smoke really badly for a while but it should clean it.

 

Yeah try cleaning the carbon out (search this site for the seafoam treatment). Something in the carb is not really shutting of the gas like it should, but if this is the only problem you have, seriously do not tinker with it. Note that the timing doesn't affect this problem, the sparks are completely shut off when you turn the key off anyway.

Don't let it keep going, if manual put it in 4th gear and with your foot firmly on the brake release the clutch and just stall it out. This doesn't damage anything.

 

thanks everyone , did find the seafoam cleaner & running thru now .