1999 VP 4.3 dieseling

[wakebrd_dad]

After running my VP 4.3 for about 1.5 hrs of wakeboarding I shut the motor off after running hard to a local island....the motor sputtered and eventually shut off....I tried to start the motor 2 hrs later...broke the starter....got towed in and removed all the plugs....found H2o in 3 of the 6 cyl....local mechanic said my motor dieseled...replaced starter..spun the motor with no plugs to remove
h20...put plugs back in and ran motor for 25 min. What else should i check? Should I put in new plugs? Thanks in advance for your replies.

 

[bruceb58]

Re: 1999 VP 4.3 dieseling

I would just be more careful next time shutting off the engine after it has been under a heavy load like that. Turn your blower on for awhile before you shut it off and let it idle for awhile to also let it cool down. Make sure your idle isn't set too high.

 

[wakebrd_dad]

Re: 1999 VP 4.3 dieseling

Thanx for the advice Bruce...this is the first time that the boat acted this way....should plugs be replaced? What else needs to be checked...my idle is a little high...i tried adjusting it down at the carb, but i have the screw basically backed all of the way off...i can lower the rpm's by pushing the throttle arm manually...how and where can i adjust the idle?

 

[dgohmann]

Re: 1999 VP 4.3 dieseling

When was the last time any form of a tune up was performed? My 4.3 started to diesel, replacing the plugs, fuel filter, rotor and cap solved it immediately. I'm pretty sure the corroded rotor and cap was the main cause (3 seasons old). I ran some techron through it for good measure.

 

[wakebrd_dad]

Re: 1999 VP 4.3 dieseling

i have just purchased the plugs/wires/rotor/cap...will do that this eevening...i have another ?...when cruising slowly...i hear a noise when i turn the wheel...the ps pump is good and the fluid is also good...any checks? the noise is not a clanking or grinding...hard to explain the noise.

 

[642mx]

Re: 1999 VP 4.3 dieseling

My 4.3 dieseled a couple times and the mechanic at the local marina said it was because of cheap gas (I was using 87, I'm a new boater and didn't know any better). I started using 93 octane and the problem went away.

I have a dumb question.... How does water enter the cylinders from dieseling?

 

[79Glastron]

Re: 1999 VP 4.3 dieseling

When a gas engine "diesels" it may change direction, ie, run backwards, and therefore suck water into the exhaust. The best thing to do is let the engine idle down before turning the key off. Also, make sure the idle speed isn't too high, and make sure the idle mix isn't too lean.

 

[642mx]

Re: 1999 VP 4.3 dieseling

Thanks for the explaination. I figured boats would have a way of preventing that with some kind of flap or something.