2005 185 4.3 dieseling

[cmassa]

I recently purchased a 2005 Sea Ray 185 that had only 40 hours on the motor (190 hp 4.3L). We have already put another 10 hours on it. One problem I have is that the motor diesels when shutting it off. I know what dieseling is and why it happens and have tried idling for a bit before shutting it off. It makes it a little better but it can sometimes run on for 10-15 seconds. High octane fuel made no difference. It's really annoying when pulliing up to skiers (my kids). I run the blower all the time when out on the water.

Some other info about our use. We are in Northern California and we have a huge variation in altutude for our boating. During the week we use it at a low altitude warm lake (Black Butte) where outside temps are 90's to 100's. On weekends we go to Bucks Lake at 5200 ft. At low elevation I use the stock 3 blade aluminum 21p prop and at high elevation I use a 3 blade Stainless 17p prop. The dieseling is definitely worse in the hotter weather at low altitude (obviously).

Other things I have heard that may help is to richen the mixture some and/or to change to a 140 degree thermostat. The temperature seems to run around 180 all the time (just above the 170 mark on the guage.)

Do either of these ideas seem reasonable to try?

Thanks,
Chris

 

[midway]

I have the 2004 version of the 185 with 4.3L, I have the same problem at times, usually I can idle with the blower running and be ok. I have noticed that the idle rpm is usually up around 900 to 1000 rpm, if I can get the idle rpm down it is not as bad, one day I will get out and play with it a little, see if I can adjust the throttle cable to make it push the throttle lever back further or maybe tweak the idle screw a little. I would leave the 170 thermostat alone, the engine is designed to run at that temp, performance is better.

 

[BonBini]

I have two ideas for this problem you may be interested in.

1) rig up an old school idle solenoid powered by an ignition source. The engine idles as expected ign on. When the sol is de energized, the throttle plate closes almost completely.

2) Vent your breathers away from the flame arrester so as the oil fumes wont be re burned. This may reduce the carbon build up within the combustion chambers. Also try running a straight weight oil so as the multi viscosity enhancers wont be fuming off as much and adding to the combustion chamber carbon build up.

 

[Sluggo33]

My 2008 with the 3.0L does the same exact thing. I haven't tried higher octane yet, but that was going to be my first try. I also try to let mine idle down before shutting it off. It's done it since the boat was new (now has 77 hours), and I've asked the dealer about it numerous times. They say it's normal (which I don't believe for one second).

Let me know if you figure out a "fix" for it.

Thanks!

 

[midway]

I will say the higher octane fuel did help on mine but still had to let it idle some before shutdown. I know what they say, nature of the beast, I am still going to try and lower idle speed just a little will help even more. My idle is always high when engine is at operating temp.

 

[quailrunner]

Same issue on our (2006 185) boat. Idling for a few minutes at the end of a run helps. I've tried one additive; the marina folks suggested Sea Foam, which I will try next.

 

[JindySR]

My 2005 came with 29 1/2 hours so hadn't done much either. From my experience fuel freshness and hence octane rating seems to have a lot to do with the running on.

I have also been told that the higher the octane the quicker it goes "off" especially if cut with ethanol.

Get the fuel level way down and then top up with fresh fuel (don't fill it right up unless you are gong to use it soon). Think about running a fuel system cleaner through it and then still make sure that you idle down for a minute or so after hard running.

Mine was really bad when I first got it. THe dealer was supposed to drain the tank before it was stuck in the container to cross the Pacific. I then made the mistake of not doing this as well and it took me a while to fully clean out the 40 litres or so of old stuff.

Running well now !or at least it was when I packed it up for winter :smt009

Good luck with it all

 

[tennisman37@hotmail.com]

I used the Sea Foam additive that is discussed in another post and it seemed to help for a while. Mine has done it since I bought it.