Pitting on piston heads..need to be replaced?

[FoolOfAFisherman]

Apparently the top 3 cylinders got hot cause all 3 look the same way however the 3rd piston's rings stuck and scored the inside of the cylinder and the outside of the piston. I looked in the cylinder and it's minor scoring and can be honed out however the piston, I believe, definitely needs to be replaced because of the scoring on the outside. The outside of the other pistons look ok, however there's lots of pitting on the other 2 pistons. Do these also need to be replaced or can they be salvaged? I know I'm not gonna be getting the best motor anyway seeing as how this is a '73 115 Merc. It's been in the saltwater and who knows what else. Just looking to cut some cost, which seem to be adding up the deeper I dig. The motors not going to last forever but I do want it to last for awhile. Any suggestions?

 

[FoolOfAFisherman]

Re: Pitting on piston heads..need to be replaced?

lower 3 pistons

 

[FoolOfAFisherman]

Re: Pitting on piston heads..need to be replaced?

#3 piston

 

[FoolOfAFisherman]

Re: Pitting on piston heads..need to be replaced?

Ok, I've done some research and it's looking more like the engine suffered from preignition/detonation. Not sure that the pistons won't work but don't think it's worth the risk. Gonna spend the 300 and get the 3 piston kits just to be sure.

 

[Faztbullet]

Re: Pitting on piston heads..need to be replaced?

That preignition with aluminum throw off from improper timing,failing trigger or weak impeller. Before you buy pistons have the cylinders miked as if tapered past spec's your wasting your money by not boring it.