2006 sea ray sport engine running on

[tpatrick1928]

What should I look for if my 4.3 Merc engine runs for up to 20 seconds after I turn the key off.

Thanks for your help

 

[Lord Farringdon]

Could be the timing is too advanced, faulty thermostat causing the engine to run hot, idling rpm too high or maybe even the wrong fuel octane rating.

Whenver I have experienced running on or 'dieseling' it has been because of advanced timing or an overheated engine.

Hope this helps


Terry

 

[Gunn]

I had this issue with my boat when I first bought it. Got the timing dead on to specs but still had it. Adjusting idle speed seemed to be the final trick that fixed it, for the most part. If I went too low with the idle speed, then it would want to stall out when the engine wasn't completely warmed up. Found the sweet spot and it is a huge improvement. I only very occasionally get it to run on for just a second or so now.

One other thing that helps after cruising, is to let the boat sit at idle speed for a minute or so before turning it off.

Other option I have read in my Merc manual (as it is a common issue with the 3.0l) is to switch to a set of colder spark plugs. But I didn't want to do this, as I would assume the efficiency of the engine would go down due to having a spark not as hot as it could be.

Tom

 

[tpatrick1928]

thanks for all your help. I will let you know what I find out.

 

[collector21]

A couple of things, first ig timing is impossible to cause this as when you turn the key off there is no timing, it is shut off. Usually it is the idle speed, and advanced timing will cause the idle to increase which causes the run on. If you back the idle down this will fix it 99% of the time. Also make sure the cold idle cam, if equiped, is not sticking and holding the idle at a faster speed after warmed up.

 

[Sea Fiend]

I think i might of had the same problem a couple of weeks ago when i turned it of the engine spuddered a little bit before it shut off, this was after i filled the gas tank from a 5 gallon plastic gas container the kind jet skiers use, i'm thinking maybe it got water or air in the tank? i'm taking it out this weekend and putting in higher octane gas and gas treatment and see what happens. Any suggestions would be apreciated.

 

[Lazy Daze]

Did this just recently start?

Did you just recently put fresh gas in? If so, was it from a marina or a gas station on land?

What does the idle RPM read on your tach?