IF you have the 400 2 stroke look on the right frame down tube. Should be a plate or etched serial number. Plus if you still have the engine sticker intact on the recoil housing,the first two digits is the year model.

 

2001

 

That's better. Pull the black wire from the reverse limiter(#30) at the terminal board and see if that helps. You wont have to push the over ride button to get full power in reverse either.The limiter module may be stuck down behind the oil tank.Just find the black wire from it. IF you haven't been pushing the over ride button in reverse it will spit and sputter above about 4 mph. It's designed that way. Just checking to make sure..

 

A lot of people aren't told about the reverse override button when they buy used. If you don't have an owner's manual it can take a long time to figure it out.