Just picked up an old Lazer Z with a 23hp kohler that was full of water. I got it cheap as it was intended to be a parts mower but I decided to rebuild it. I got the motor running within a few days and discovered that the right side hydros do not respond. With engine off the right side drive wheel will freespin but with engine on it spins about half turn then stops. Lap bar in full forward or reverse will only cause the wheel to twitch (in the opposite direction) and puts a pretty good load on the engine. There are no grinding or moaning sounds comming from the pump or motor. The hydrolic fluid is full of tiny bubbles and there are no signs of fluid leaks. I tryed bleeding the system from the bypass valve and the fluid comes out aerated and fairly slow. Any clues there if im looking at a pump replacement/rebuild or possibly wheel motor?