70 HP johnson busted block

[prcacowboy08]

Hello I bought a 1979 Skeeter bass boat and the guy said he could not get it to plain out. so I carried it to the lake to check it out and found it needed the carbs cleaned. After cleaning the carbs I carried it back to the lake and it ran fine until about 20 minutes of full speed and it popped really loud and lost power. I brought home to check it out and there was water in the #3 cylinder I then tore the enine down to find it busted the block where the bearing comes around on the crank shaft but the bearing wasnt thrown. What could have caused this and does anyone know where I can get a used block for a 70 HP johnson.

 

[tx1961whaler]

Re: 70 HP johnson busted block

The last guy may have ran it way too long with clogged carbs, and one of them was running way too lean and the piston froze.
Or the head gasket leaked water in the cylinder and it hydrolocked.
Or he ran it without mixing oil.
Or he did one of a dozen other things that could cause an engine to seize up.

There's one here, but you wouldn't like the price:
http://www.boatmotors.com/motorparts/index.cgi?pid=6492&flag=2&hp=70&year=1979&state=tx