1989 125 force outboard bored .040"

[lakelover68]

I have a factory bore outboard. I just replaced head gasket but still have a power loss as compared to prior breakdown. One of my cylinders was slightly scored............no such thing as slightly I know just wishful thinking. If I bore .040" over what would that give me in a hp or displacement increase. I can get Weisco set of 4 with wrist pins, rings and clips for around 400 $ before shipping...........Gotta like the Canadian Dollar now !!!
All of my electrical is good and I have a lot of cdi's and coils etc from ebay so over boreing may be the way to go ???????

 

[Nate3172]

Re: 1989 125 force outboard bored .040"

I don't recommend going straight to a 40 overbore if you don't have to. Only upsize to what you need for the cylinder/s to come out right. If you go straight to 40 and by chance something happens again in the near future than you have limited your options as far as re-build goes and may have to replace the sleeve/s.

 

[Frank Acampora]

Re: 1989 125 force outboard bored .040"

As Nate said, don't go straight to .040 unless it is absolutely necessary. The engine displacement will only go up about 2 inches and that's not enough to see a noticeable horsepower gain. In addition, the cylinder walls are now getting a bit thin and less resistant to heat--especially the webs in between the exhaust ports. AND if that's not enough, with the same block called Chrysler---factory recommended NOT to bore more than .030. They must have had a reason.

Of course, there is always re-sleeving, but not every shop can do it and it is expensive.

And as far as I am concerned, WISECO is the way to go for pistons

 

[Nate3172]

Re: 1989 125 force outboard bored .040"

You would be surprised, Frank, how easy it is to re-sleeve one of these Force engines. I will not post it here for fear that a little bit of knowledge can be dangerous and I'm afraid someone would take only part of what I say and destroy there engine block. I would be glad to share it with only people who are comfortable enough with there mechanical aptitude and skills to perform such a job on there own. It does work well and have done this to many a 2-stroke engines.

 

[tydog]

Re: 1989 125 force outboard bored .040"

hey was reading your post about re sleeving i have a 1990 mariner 3 cyl 75hp and am thinking about doing it how did you do it?