1979 140 keeps running briefly when engine off

[boboy]

Additive i can add to stop engine from doing this? Thanks Bobby

[tst]

check ignition for point gap and timing, also make sure base idle speed is correct

[Eugene]

Ignition timing most likely fault.

Second, hot spots in combustion chamber. SeaFoam or carbon remover in a can if adjusting the timing doesn't work.

Edit. Flush the cooling system. Remove sediment from bottom of and around the cylinders.

[boboy]

Thanks i have had tractor about 5 years or so and never looked at points as it cranks and runs good but shutters when engine quits and black smoke blows out breather. Bobby

[Eugene]

Complete engine tune up time.