50hp Mercury Blue Rebuild Question

Hey guys,
I've bought a boat with no comp on one of the cylinders on a 50hp Mercury blue stripe.

I'm wanting to know if this is something i can bite off ymself with help from the manual. I've rebuilt car motors before, and i've built myself a couple race cars (crashed first one )

Im quite technically minded, and have a good understanding, but know that being a 2 stroke, being carbie, its going to be quite different, albiet, alot more simplified, though very different.

I'm assuming that compression drop on the cylinder is likely to be a dead head gasket, and not likely a warped/cracked head (assuming again, that these motors have the same basic design as a car). Is it just a matter of opening the head, having it decked, and replacing the gasket? Obviously, if its more, than the crank comes out for a balance, the rods get inspected for fracturs, and the pistons get a clean/replace with new rings?

Or being an older motor, on a later hull (1988 4.7m Caribbean), should it be time to start looking for a newer motor?

Cheers,
jase

I had a scored cylinder on a 50 hp mariner causing low compression, one of the carbs leaned out an not enough oil. no head gasket, 2 machined surfaces you put together with
loctite pro seal. the block was a one piece sorta alum. design that there was no way to machine because it bottomed out instead of going strait thru.( thats where the spark plugs went) bought new block and rings. also needed a special tool to get the flywheel off. luckily all bearings were good. intake valves were a reed block so it just had exhaust valves. got a mariner manual, put back together and did timing, was easy but frustrating.

http://www.marinepartsplus.com/catalog/mariner/serial/50_3_CYL/+16404/336-90

You CAN do it yourself, and I'll happily walk you through it. Most likely you have a scored piston whose rings are thoroughly stuck. I've fixed bunches of these, usually by simply honing the bores, then cleaning up the pistons (and re-ringing). Getting those pistons back in--from the 'other side'--will teach you a few new words, but you can handle it. While apart, I suggest you replace the crank seals as well. And buy a manual (from this site, please).

Jeff

Yes buy a manual,and, as Jeff says from this site.I and if you decide to rebuild,the parts prices aren't bad either.but Andrew doesn't ship parts international.These headless blocks can be bored out,I got away with a honing and new rings and did the bearings while I was in there.