1989 Evinrude 150 XP piston/bore size.

[mxme788]

I just purchased a rebuild kit for my 1989 Evinrude 150 xp. The pistons are GLM pistons stamped 0.040" over P/N 24034. I am planning on getting the block bored to 3.540" and wanted to double check this is the correct bore before proceeding.

Thanks,

Evan

 

[Faztbullet]

Re: 1989 Evinrude 150 XP piston/bore size.

Why so big? Are cylinders that damaged? The finished bore size will be 3.540+/-.0005 and you will need to update the high speeds .002 bigger.

 

[mxme788]

Re: 1989 Evinrude 150 XP piston/bore size.

Faztbullet thanks for the reply. The reason for going so big is that I took the block to a machine shop, they measured it and one of the cylinders got hot and most likely warped they said. I believe this was caused from the rings in that cylinder being seized to the piston, which was the cause of the teardown/rebuild. Could you explain a little more about the high speeds?

 

[Faztbullet]

Re: 1989 Evinrude 150 XP piston/bore size.

The high speed jets are in the fuel bowl on each carb(6 total) behind the drain screws. These supply the proper fuel rato to the engine, you can go up to .015 oversize without changing but anything over .020 oversize I always rejet. Your engine should have 65C jets and if going to .040 I suggest you go to a 67C (part#317183)jet for every cylinder bored to that size.

 

[mxme788]

Re: 1989 Evinrude 150 XP piston/bore size.

Thanks again Faztbullet that will for sure help me out.