Re: Mariner Rebuild cost.
I just rebuilt a Johnson V-4 Crossflow. New Pistons (and rings), two cylinders honed, two machined, gaskets, carb kits, and sealant for about $650, time elapsed was 30 days.
I knew what the failure mode was, so I was able to reuse bearings, crank was great, and all electrical was fine. I did all the work myself except machining.
When I did my 120 hp Sport Jet boat a few years before, I let the machinist talk me into letting him assemble my engine. I also had a crank which had to be built up and reground. That one was closer to $2500 when I was done, time elapsed was 120 days.
iboats is great for parts, but I would phone them, the website seems incomplete. It also helps to have a NAPA Marine catalog because the part numbers are the same as iboat's.
Good luck!
fp