Jetski/outboard rebuild

[burt_066]

why is it when I rebuild an outboard I can have one cylinder taken 30 over without changing the others. With jet ski it looks like thats never done. If you rebore one you do all of them? Thanks Bobby...

 

[Jeff Walkowiak]

Re: Jetski/outboard rebuild

you don't need to, but most people can't understand the concept of doing just one, They think it will be out of balance or something.

 

[Silvertip]

Re: Jetski/outboard rebuild

In a rebuild where only one piston is being replaced, if the replacement piston is the same weight as the original there is no difference in reciprocating mass so balance is not an issue. If you use an aftermarket piston however, it is probably wise to weigh it and compare it with the original. Otherwise its a good idea to replace all of them.

 

[Jeff Walkowiak]

Re: Jetski/outboard rebuild

on a 2 stroke engine the piston moves down under force on each stroke and the weight of the piston itself isn't really that critical to the balance of the spinning crank shaft and that it why a lot of people can get away with just punching out one hole and using 1 oversize piston, with no noticeable issues, I have done it many times and there is no problem.
The first time I was told this I didn't believe it either.