Please Help !!

[Starcraft 15]

Can anyone help me on this one, I have a 1968 55hp Evinrude with worn pistons. the original part number is 0383144 (.020 o.s. ) This is no longer available and is superseeded by 0386257 ( also .020 o.s. ) This P/N is also no longer available but, Wiseco makes a piston P/N 3115P2 that they say replaces 0386257. With the 3115P2 you also need to replace the upper rod bearing with a WP15-1 ( 3/4" instead of 5/8" ) . Has anyone done this with this particular outboard ? The Wiseco is has 2 rings - the original has 3, will that make any difference??? I really need some help on this one !!!!

 

[F_R]

Re: Please Help !!

No, I haven't done it, but just want to say that Wiseco has a good reputation and should know what they are talking about. As for the two rings, are they pressure-back type? They are far superior to the old 3-ring type pistons.

 

[Dhadley]

Re: Please Help !!

That is true, the 3115 will work. The original OE piston had 3 square rings. The replacement, 386257, had 2 - a pressure back top ring and a square second ring which is typical of the OMC design. The Wisecos use a keystone design on both rings almost exclusively thru the outboard line. The Wiseco bearing is part # B1029.

The 2 ring piston will work better than the 3 ring design. Better sealing & less drag.

I bet you weren't talking to Wiseco, bet it was Pro Marine. Right?

 

[Starcraft 15]

Re: Please Help !!

Thanks!! You guys are AWSOME! Now I can put new life into my old motor. I have recently rebuilt the lower unit , ignition system and carbs. After running the motor and decarbing, I still was only producing 85 psi in all 3. After a tear-down I discovered surface rust in the bore and about .020 Piston - to - bore along with .015 in the wrist pin boss ...................So, with boring .020 and new pistons, it should be back to new again!! And yes your right Dhadley, I was talking to Pro Marine. One question thou,........... Is Wiseco bearing P/N B1029 the same as WP15-1 ? I assume they are both used with a 3/4" wrist pin??..............Thanks again guys !! I REALLY appreciate your help !

 

[Dhadley]

Re: Please Help !!

Yes, it's the same bearing. Each company uses their own part number.

The piston you'll get has a much larger diameter wrist pin than the pin you have in the OE pistons. That's why you have to use the different bearing.