2005 4.3L Mercruiser Dieseling (throttling up and down after shutting off) - SOLVED

[samuelahickman]

Hello-I'm new to boating and have used this site extensively since buying our 2005 Sea Ray 185 Sport w/4.3L Mercruiser (60 hours) in August 2017. It had a dieseling problem right away. We'd run it hard, then turn it off and it'd throttle up and down, sputtering for a few moments before eventually dying. It's been solved though and I wanted to share the fix with the community in hopes it helps someone else.

FIX: In neutral, the boat was idling around 900 RPMs but the engine sticker said it should be at 650. So, we found the idle screw and turned it (flat head screwdriver--very easy), until the RPMs sat at just over 600. Ontop of that, we try let it cool down for a minute or two after running hard (tubing, skiing, etc.)

Since making those adjustments, no more dieseling!! Hope this works for you!

 

[Bt Doctur]

check the timing too, that can contribute to the same problem

 

[TyeeMan]

Yep, high idle will do that, as Bt Doctur said, check your timing as that can be a big factor as well. Also, I never shut down directly after a hard run, I let it idle for at least a couple minutes to cool everything down a bit.