1992 4.3 Mercrusier... HORRIBLE plugs.. take a look and give me some direction..

[jayp0629]

1992 4.3 mercrusier.. just bought the boat.. guy told us he winterized it ( had recipts to show) we got it going and it idled fine, started to drive it and it would bog... the throttle would go eratic then it backfired and died... restarted it, slowly got back to the dock.. i drained the gas to change it and pulled the first plug and saw this..

so whats causing the plug to look like this?

 

[achris]

Re: 1992 4.3 Mercrusier... HORRIBLE plugs.. take a look and give me some direction..

It's the wrong plug! For that engine you should be running NGK BR6FS or AC-MR43T. Those plugs are for the later engines, and they are too long for those cylinder heads.... Start with a fresh set of the right plugs, and a compression test...

Chris........

 

[jayp0629]

Re: 1992 4.3 Mercrusier... HORRIBLE plugs.. take a look and give me some direction..

ouch thats a kick in the butt. what an idiot... how do you change the plugs and put the wrong one in?!?!!?! ugh

 

[Bondo]

Re: 1992 4.3 Mercrusier... HORRIBLE plugs.. take a look and give me some direction..

ouch thats a kick in the butt. what an idiot... how do you change the plugs and put the wrong one in?!?!!?! ugh

Ayuh,.... Welcome Aboard,.... I'd also think ya got a Fuel delivery issue,... or lack of it....

Clean the fuel system, from the tank, to the carb, rebuildin' whatever needs it...

What'd the gas Look like, 'n Smell like, that ya took out,..??


Btw,... Good call Chris,...

 

[Don S]

Re: 1992 4.3 Mercrusier... HORRIBLE plugs.. take a look and give me some direction..

From the looks of that plug, not only do you need a full tuneup, but you need to do a compression check as well.
Here is how to do a compression check that means something.

View attachment 97-25 Compression Test.pdf