4.3 mercruiser stalls out and has black residue on plugs

[rinkerthestinker]

I recently boat a rinker captiva 190 iwth a mercruiser 4.3lx that sat for a year. It continues to stall after a new fuel pump and carb, which is makibg me thin, it warms up and the pickup coil is seperating and losing continuity. During trying to find my problem I pulled a plug and noticed black on it, although it doesn't smoke as if oil is getting in the combustion side of things. Is it possible this is just bad gas in there, bc literally doesn't smoke. It drops oil pressure sometimes then I shut it off and check oil lrvel and is always good. What could this be? How can I check the oil pressure switch?

 

[Fishermark]

Re: 4.3 mercruiser stalls out and has black residue on plugs

A little more info is in order. The pros will want a serial number to narrow down all the specifics... but even a year or type of ignition system will help.

 

[Fishermark]

Re: 4.3 mercruiser stalls out and has black residue on plugs

And the black residue is probably carbon indicating a too-rich mixture as opposed to oil.

 

[rinkerthestinker]

Re: 4.3 mercruiser stalls out and has black residue on plugs

Motor serial number 0f274776
drive 0f239925
and thrunderbolt iv ignitin system

 

[Failproof]

Re: 4.3 mercruiser stalls out and has black residue on plugs

New to you boat should mean a complete tune up first thing. And a full service of the fluids and filter. Unless of course you have undeniable documented and certified proof it was done recently(this year). This is just my opinion, but it takes alot out of the equation.

 

[rinkerthestinker]

Re: 4.3 mercruiser stalls out and has black residue on plugs

i know this sounds dum, but this is my first boat what does a tune up all include?

 

[Bondo]

Re: 4.3 mercruiser stalls out and has black residue on plugs

i know this sounds dum, but this is my first boat what does a tune up all include?

Ayuh,... Welcome Aboard,... Fresh sparkplugs,.... AC Delco, MR43T in yer case,...

Inspect, 'n test the plug wires,... inspect, 'n/ or replace the cap, 'n rotor....

Do a compression test, 'n leak-down test,...

Inspect the contents of, 'n replace the fuel filters...

Set the timing, 'n idle settings, 'n any other carb tunin' needed....