Need Help On Rebuild of 25 Murcury

[peek]

Doing the rebuild I have already split the case and removed the crank and pistons......had one burnt piston (the cylinder wall looks fine) But the side with the burnt piston has some scoring and metal damage in the dome....But nothing on the wall...this model mercury does not have a head...everything pulls out from the crank side......And my Question is Should i remove the scoring and if so how....are just clean it up and leave it there???

 

[hondon]

Re: Need Help On Rebuild of 25 Murcury

Yes ,you will have to remove that scoring completely or you are wasteing your time.Hopefully the scoring is not deep enough and can be honed out but more likely you will need to bore that cylinder oversize with a new piston and of course new rings all around on both.Finding a place that will do quality boreing on that block may be your biggest challenge.

 

[peek]

Re: Need Help On Rebuild of 25 Murcury

Thanks for the advice.But the cylinder wall is ok and micrometer.shows perfect....It is in the dome that the pitting is in......How should i remove it.On this model there is no head...everything pulls out from the crank side ...and i am trying to find out how i can best get in there to remove the scares...........HELP

 

[FlyBoyMark]

Re: Need Help On Rebuild of 25 Murcury

Certain Mercury 25 HP have Chrome bores....honing must be done exceedingly careful and not to much. If the chrome is removed and the steel exposed...the engine needs to be rechromed and the cost equals a new block.......