update on my 1991 Johnson 70HP powerhead.

[Gamecock66]

I can't find a machine shop around here that will look at it. What happened is the waterpump went bad and the #2 piston scraped the cylinder wall. The piston is pretty much junk due to the oil ring welding itself into the groove. The cylinder is scratched but not cracked or otherwise damaged. What I am thinking is to use my cylinder hone and hone out the scratches in the bore as well as the other 2 cylinders and then replace the one bad piston along with all new rings, bearings and gaskets. Here are a few questions I have though.

1. Will this work?
2. If I hone do I need to go oversized rings?
3. I am having a hard time finding a suitable assembly manual to put this thing back together with. Any suggestions?
4. What is and who has the best budget overhaul kit?
5. Any other advice?

Thanks
Wade

 

[faztbullet]

1. Will this work?

Doubtful...you need to remove aluminum transfer and use a rigid hone, a spring hone is only good to break a cylinder glaze and it will follow a out of round cylinder wall.

2. If I hone do I need to go oversized rings?

No as oversized rings will not fit a standard piston......

What I am thinking is to use my cylinder hone and hone out the scratches in the bore

If its been hot you need to mike the bore to see if they are out of round,if so they will need to be bored oversize. If the cylinder is over the .003 wear limit ,bore it.