Mercruiser 4.3 problem.** SOLVED :) **

neilmw

Petty Officer 1st Class
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Jul 19, 2004
Messages
245
Re: Mercruiser 4.3 problem

Re: Mercruiser 4.3 problem

Any ideas ??
 

97VP57GSI

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Jun 28, 2007
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Re: Mercruiser 4.3 problem

Re: Mercruiser 4.3 problem

Need more info: Year, Fuel Injection, ...etc?

What you are describing can be a large list of things. If you don't want to take it to a Marine tech then you are best starting with the basics and least expensive. Had a similar problem with a 4.3 Merc which ended up being water in the tank. Dumped water separator/filter into a clear container. Watched for water fuel separation (fuel goes to bottom). Found out it was nearly 100% full of water.

Then again I had as similar problem with my Volvo Penta 5.7 EFI. Ended up being a bad connection at the main engine wire harness connector. Started out by replacing the filter though. Then went looking for lose connections. These sort of problems take patience and strong troubleshooting skills and logical thinking. Got to list out all possibilities, then start eliminating each item starting with the most likely or least expensive (connections, filters). Some things you can test, some things you can check. You may end up with a few items that you can't test and may have to start replacing things.

Take what you get here as "suggestions". The most you will get is and educated guess, as long as you have educated us :) Meaning, give as much info as you can (equipment information, all symptoms), leave out what you think the problem is.
 

neilmw

Petty Officer 1st Class
Joined
Jul 19, 2004
Messages
245
Re: Mercruiser 4.3 problem

Re: Mercruiser 4.3 problem

Sorry, I have only given half a story.
Its a 1992 merc 4.3l Carb with thunderbolt VI ignition.
The problem is that there is no spark at the plug, I have replaced rotor/cap and coil and am at the moment trying to check all the connections. The one thing I have noticed is that there are no wires connected to the shift intterupt switch, although I did not do this and the engine was running with no problems so I am guessing that this has been bypassed.
 

bbrnhart

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Joined
Sep 9, 2006
Messages
28
Re: Mercruiser 4.3 problem

Re: Mercruiser 4.3 problem

I just had an episode with my 4.3L. Mine would die suddenly whenever it felt like it. I could go 1 mile I could go four, I could go ten. I changed coil with no improvement.

I changed plug wires, cap and rotor, and fuel filter/water separator. Something there fixed it. The guy I bought the rotor from told me to wear gloves when I pull the rotor as he cut the heck out of his hand when it came loose. Mine slipped right off and was pretty loose on the shaft. The rotor he sold me, someone wrote on the box to use lock tight when installing. I suspect that it may have been the rotor moving up and down on the shaft?? Either that or the filter plugged with water. If I waited a few seconds after it died the motor would star right up. Except once it would not start for about ten minutes.
 

neilmw

Petty Officer 1st Class
Joined
Jul 19, 2004
Messages
245
Re: Mercruiser 4.3 problem

Re: Mercruiser 4.3 problem

I had to use a cutting tool to get the old rotor off and the manual does say to use locktite on the key way, but the new rotor was quite a tight fit anyway. i have recently changed the fuel/oil filters so hopefully they should be fine. I started on the troubleshooting list for the ignition and replaced the coil as I was not getting a spark, but before I replace any more parts I am going through and rechecking all connections, not sure how and where the safety lanyard kill switch connects to as i though i should check it.
 

neilmw

Petty Officer 1st Class
Joined
Jul 19, 2004
Messages
245
Re: Mercruiser 4.3 problem.** SOLVED :) **

Engine running fine today, found a couple of faults, 1, the new rotor i fitted had a crack down one side, 2, coil lead not making a good connection. After a while of turning over it eventually fired up and is now running very smooth and starts on the button, thanks for all your help. Best piece of advise I had and can offer---CHECK CHECK AND RECHECK before throwing money at it and buying parts, i was very close to buying a new sensor then the module if it hadnt worked.
Well thanks again chaps !
 

labguy3232

Cadet
Joined
Jun 12, 2007
Messages
14
Sorry

Sorry

Don't mean to ask a question from someone else's thread, but I cannot get into the "Mercruiser/OMC I/O" forums. Anyway, I need to know how to remove my outdrive from a 1986 Bayliner Capri with 3.0L OMC I/O. I see where there are 6 bolts along the outside (3 on each side). Are those the ones I need to remove or should I be looking somewhere else? Thanks for the advice and again, sorry to butt in on someone else's thread.
 

Bondo

Moderator
Staff member
Joined
Apr 17, 2002
Messages
70,526
Re: Sorry

Re: Sorry

Ayuh,...... Don't feel Lonely,....... This is the Only thread I can get into as Well......

Pull those 6 nuts,+ the Trim Rams,.... Then the Outdrive will come Off.....
 

labguy3232

Cadet
Joined
Jun 12, 2007
Messages
14
Re: Mercruiser 4.3 problem.** SOLVED :) **

Thanks. I have done that and have pulled, tugged, and yanked and it will not come off. Do I just need to continue yanking and pulling :p until it finally gives??
 
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