OS 91PS motor help

[SKYBLUE]

I just bought a new OS91PS motor and wondering if you guys can give me any helpful infos I need to know about this engine and also some hints and tricks on tuning. Also which washers do I use when installing the Fury metal fan to this engine? Do I just follow the instructions from the manual; stock washer against front engine bearing, lower and upper collets, and a 0331 washer under the crank lock nut or do I need any other washers? Also how much of the OS 91 head do I need to shave off inorder to fit the fan shroud over? Any pictures on that? Your helps appreciated, thanks.

[DavidH]

Skyblue,
First I would suggest to run some fuel thru the pump without it connected to the carb. Take the line loose from the carb, and turn the motor over with a starter and let some fuel flow thru the pump without it going to the carb.

I put the fan on the PS just like the instructions state to install it.
I have the top fin cut off the PS head and about 4mm shaved off each side of the head. It fits in the fan shroud with those mods and there is not any overheating issues for me.

David