Piston damage.....1988 Yamah 50

[walrus98]

When I pulled the head off my 1988 Yamaha 50Hp, I discovered the gasket had been leaking and the piston is damaged at that point. The piston is partially eaten away exposing the ring. It looks like it partially "melted." <br /><br />Question: Might replacing the gaskets be all I need to do, or does the piston have to be replaced also. Obviously, there is a big difference in labor involved! I own the engine so it won't be a repair liability issue.

 

[bonitoman]

Re: Piston damage.....1988 Yamah 50

If the piston is damaged then the motor will have to come apart and be rebuilt. What does the damage look like? Is part of the head of the piston gone?

 

[walrus98]

Re: Piston damage.....1988 Yamah 50

Yes, part of the head of the piston is gone, enough to expose about a half inch of ring length. The piston in that area is lumpy and looks like it's melted. The rest of the piston looks Ok as do the cylinder walls.

 

[Ray Neudecker]

Re: Piston damage.....1988 Yamah 50

It will need to be rebuilt. The sleeve needs to be checked once the piston is removed. Unlikely that there is no damage to the sleeve. Boring will likely be in order.