Spark Plugs and oily?
 

I'm being a bit paranoid I hope, but since I bought my boat last fall I have almost been expecting something to be wrong with the motor since I got such a great deal, and I bought it from a race car driver. I just cant find anything wrong, although I do not know why I didn't think of removing and inspecting plugs until now but I didn't.

So upon removal realized they are very black and burnt, I do get a very little bit of smoke from the exhaust but didn't really feel it was enough to worry about but it seems that there is a bit more oil in the plug and around the plug than should be.

Any thoughts on oil in plug area, even some on plug? Is it simply running rich?

And the plug itself, what was in it is an AC Delco .MR43T , is this the correct plug for a 94 5.7? And if not please recommend the correct ones and any other help you may have for me.

I just finished completing the closed cooling system upgrade and would like to give the old girl a few more good years before a rebuild.

Thanks for your thoughts, I appreciate the experience we have here in this group that we can all benefit from.

Re: Spark Plugs and oily?
 

Zack,
As per the manual, your plugs should be Volvo Penta 3854400-3 or AC-MR43T for a 94 5.7 litre.
Will wait for others to answer the rest of the questions.

Re: Spark Plugs and oily?
 

Well, now realized where I think the oil is coming from. The breather tubes from the valve covers to the spark arrestor at the carb. I think I have an extra ordinary amount of oil here that seems to be coating the engine. Maybe blow by from the rings????

I took it to a Mercruiser dealer today to get compression check and professional advice. Hope for the best but I am worried I have some ring troubles maybe. Anyone deal with this? Am I up for a rebuild?

Re: Spark Plugs and oily?
 

Well, good news back from the Merc expert. When the last techician filled the oil level he left it 1 qt high! There was an excess of oil (that I didnt catch) and that was allowing the blowby condition. So all is well, compression tested perfect and I am so happy that I have a good bill of health on the motor. He removed one quart and all is well.

He did find a weep in the block water pump I need to look into. May need to replace this water pump, but that doesnt scare me like a blown cylinder or rings.