about 200 - that's what sucks so bad about it. i have only had the thing for a few months.

This is a merc 502 carburated and they are champion plugs. I just bout the boat and the engine was just gone through by More Power and they put in Champion 4025 "Truck Plugs". Should I be using a different plug and what compression should I expect out that cylinder? Thanks for the input...

it look like you have something hitting those plugs. poss dropped valve

i would not run champion plugs in anything other than a lawn mower and even then as a last resort.

I figured that it would be chipped up and that if something (valve) hit it but it doesn't look like that. It looks like it arched itself off and the metal is beaded up like welding splash... I dont know and I figured I would have heard some clings and klangs in the cylinder when engine is turning over if a vlave was broken, wouldn't I?

that is not from lean run, thats from something bouncing around, pull the heads !!!!!!!


And the above post IS CORRECT....NEVER NEVER NEVER RUN CHAMPION PLUGS.......

JUST NGK OR AC DELCO MR SERIES

I feel for ya gofast....When I bought my boat I put 2 hours on her and she shut down. 1 plug looked beat up like that and I had dropped a valve.......Turns out the piston was in bad shape and the cylinder had to be sleeved (complete rebuilds!!!)

more then likley it does need rebuilt but by pulling the head it will tell the story......

Thats all I was saying

If it's only 200 hrs and they are stock motors, I would leave the good one alone. If they have been modified, maybe look for causes why the valve or piston came apart. Reversion or cheap replacement valves come to mind right off.

Yes that plug is beat up pull a head so you can get the bad news over with Good Luck.

ouch.. Pop the HD off. The odds aren't sounding like they are currently in your favor. Here is a small ray of hope, If it only had a vale problem you may be able to squeak by with re-doing the head. Just make sure the cylinders weren't scored at all and that the pistons dont have holes or any large divots. Keep us all posted as to how you make out.. J