Head gasket replacement ???s...

I took my boat in today and got it checked out. Everything is fine with the timing, carb, basically everything -- BUT -- Its only running on 2 cylinders! There was basically no compression on two of the cylinders. Using the motor oil in the cyl trick, we determined the rings to be OK, so we're going to change the head gasket out. First things first, we'll get the head off and inspect for damage.

Where is the cheapest place to get a top end gasket set for a 1987 3.0 Merc? NAPA maybe? If not, where would be the best place? Does anyone have any part numbers for kits so I can search the net and compare?

If it ran likes this (http://www.youtube.com/watch?v=a3EqwR-Bods) on two cylinders, I wonder what it'll be like on all four!!

Re: Head gasket replacement ???s...

It wouldn't run like that on 2 cylinders, trust me, It wouldn't run like that on 3 either. Each cylinder is 25% of the power.

Re: Head gasket replacement ???s...

I don't think you were only running on 2 cylinders. The engine wouldn't even idle if it were running on only 2 cylinders.

Have a great day,

Rob.

Re: Head gasket replacement ???s...

it was running on all four in the video..

Re: Head gasket replacement ???s...

If you really think you're missing a cylinder (I didn't watch the vid- dial up), feel the ceramic part of each spark plug after running the engine and turning it off. If they're hot, they're all firing. Just don't touch 'em with the engine on, unless you want a sample of what a stun gun feels like.

Re: Head gasket replacement ???s...

Ok, so... If I had little to no compression in 2 of the cylinders and nothing else has changed since the vid, what am I to assume? Any ideas?

Re: Head gasket replacement ???s...

First I'd recheck compression (properly- all plugs out, fully charged battery, throttle wide open, note readings dry, add oil to cylinders, retest,note readings) and make sure that you really have a compression issue.
Zero on 2 cylinders (especially if they are not adjacent) is unlikely.

Re: Head gasket replacement ???s...

I'm gonna get a compression gauge and test it myself. Since I'm not technically starting the boat, can I do a compression test on land w/o hurting the impeller? It was in the water yesterday when the guy was checking it out.

Re: Head gasket replacement ???s...

Yes