5.0GL won't die

[medic1720]

My 5.0 GL won't die immediately when I turn the key off. Still sputters so I turn the key back to crank, then off,,,,, more sputtering,,,, so on and so on until finally 4th or 5th try, it dies when I turn the key off. Why does it do this and how do I fix it?

 

[Maclin]

Welcome aboard!

Did this just start happening? Has some recent work been done on it? When was last tuneup, were correct parts used, etc.

Good luck!

 

[medic1720]

Welcome aboard!

Did this just start happening? Has some recent work been done on it? When was last tuneup, were correct parts used, etc.

Good luck!

It's been happening over a year. No work done and no tune up.

 

[Maclin]

How long have you had the boat? Do you know when the last time any work like tuneups, etc were done.

Lots of things can factor into that symptom.

• Idle set too high on carb.
• Improper heat range spark plugs.
• Ignition timing not in spec.
• Dirty or otherwise restricted flame arrestor if a 4bbl carb, can cause high idle.

I had a 570DP 5.7 and if I did not let it run for just a minute or so in hot weather before I turned it off sometimes it would do that.

May just be time for a tuneup.

 

[89retta]

Sounds to me like you have a lot of carbon build up on the pistons. Causing it to diesel. Change your spark plugs and add some seafoam to the gas. It should clean it up

 

[Insomnium]

Probably a filthy engine and crap is still cooking keeping it firing. Mine did that with older gas that lost its octane and the carb needed rebuilt. Too many deposits, older low octane gas, engine dieseles a bit.

I cleaned and rebuilt carb (easy) drained and cleaned tank, ran better gas. No problems since.

 

[Big dawg 23]

Sounds like incorrect timing and it’s dieseling, like a few have suggested.

 

[Bt Doctur]

If not corrected it will cause a hydro-lock condition too