Re: Mercruiser 3.0 Rebuild- suggested threads?
I rebuilt my 140HP (3.0L) a couple of years ago and bought a complete engine kit off Ebay, about $400. All of the parts were name brand good quality stuff, I don't remember the seller though. Greenbaypartsworld also sells rebuild kits for the 3.0. Make sure to get the 1 piece oil pan gasket as it's much better than the 4 piece set and don't get a high volume oil pump, the std oil pump is what you want.
I had the engine bored to .030, head rebuilt, rods checked, pistons pressed, crank turned 10/10, total machine shop charges were around $400. I did all of the engine assembly, though the shop would have put it together for another $100.
Just because you have rusted cylinders does not mean the block is cracked, water could have came back through the exhaust. My cylinders were rusted from sucking water a couple of times, bad exhaust shutters. If the engine was a runner and wasn't getting water in the oil, you should be fine. If the status of the block is unknown, I would have it pressure tested and magnafluxed, same for the head and manifold if they are in unknown condition. Actually, with water marks in the cylinders, I would carefully check the manifold and riser, and their mating surfaces as this is another area where water could leak back into the engine. If it's in your budget, replacing the manifold and riser might not be a bad idea, especially if you are in saltwater.
