Piston replacement for 150 XR-6

[JDusza]

I am working on a 150 XR-6. At least the serial numbers fall to that parts list. The power head and drive train have not been replaced.
I ordered the piston and it ends up being woefully undersized for the cylinders I have. Mine measure 3.491 inches (all 6) and the replacement measure 3.210 inches.
Any ideas on how I get to the right piston?
Thanks.
J

 

[Faztbullet]

Those are 2.5 piston spec and replacement piston I don't have the slightest idea as those measurements don't fit a 2.0L or 2.4L piston...

 

[CharlieB]

Did you get the serial numbers off the engine mount or off the soft plug in the engine block?

You may have a 'FrankenMerc'. Someone may have replaced the motor at one time. This makes it very difficult to correctly identify parts needed for rebuild. You may have to search service manuals for 2.5 and hopefully find the pistons specs your currently have. Once verified what motor your block really is then you can proceed with your repairs.