Hello all new to the forum. I have a JD 757 mower with a 25hp kawasaki motor. I believe the motor is a FH721D The motor had went on this and I have rebuilt the motor but cant seem to figure out this issue of getting oil in the carb. When I rebuilt the engine I had to have the cylinder walls bored out. I put new pistons for the oversize bore with correct rings. All new gaskets throughout used the service manual that I got offline to guide me through. I did reuse the carb an air cleaner but replaced the gaskets and filters. I did some research and found suggestions saying that it could be the breather so I went ahead and replaced that as well. Still have the same issue. Any help would be greatly appreciated as I would love to have this mower back up and going.
Try this and let us know what happens. With the engine running at 3/4 throttle, pull the oil dipstick and let it rest on top of the tube. Does it bounce around, like there is a lot of pressure pushing air out the tube? I'm thinking maybe the rings were not spaced properly or the rings did not seat. This would cause oil to be pushed out the breather into the carb. Did you space the ring end gaps 120 degrees apart.
