merc 65 keep or trash?

my grandfater passed away a few months ago and I found a 65hp Merc in his shop. I don't know what's wrong with it but I seem to remember him saying he bought it for the lower unit. It's all there, just wondering where to start? It looks like the battery cables are melted?! How can I test a motor this large? I have a 55g drum for my smaller Johnsons but I don't even know where to start on this large a motor.

Re: merc 65 keep or trash?

I have the same motor that I just bought I took it out today for the fist time It went great..I think you should keep it

Re: merc 65 keep or trash?

I would start by taking plugs out and see if you can turn the flywheel clockwise by hand. If it is seized up no point in salvaging it. Burned out cables is telling me it would not start. If you can turn by hand you can get muffs for the water supply. You should drain the lower unit oil and see what that looks like. If no oil comes out it could be filled with rust. Turn flyweel by hand and shift to see if prop changes direction. Remove lower unit and replace impeller. Shoot a couple of squirts of oil into each of the cylinders. Put new cables on and see if starter will crank. IF not take starter apart and check condition of brushes. You can do all of this stuff for nothing. IF nothing looks too bad then do a cold compression test and see if it has a blown head gasket.