Jim Stewart

i have a 1998 John Deere 345 lawn tractor. approx. 900 hours. tried to start this morning, engine fired instantly as usual then it made a slight noise, similar to a backfire and then it stalled. tried to restart and the engine spun over too easy. I pulled the plugs, I have compression in the left cylinder and no compression in the right cylinder. The engine is clean, uses no oil and oil is changed every 50 hours with 10-30 Mobile 1 and NAPA 1394 oil filter. Any idea where to look?

Is it a flat head, that has the valves in the head? If so, pull the head on the cylinder with no compression, and see if a valve seat popped out. If it did, drive it back in all the way around with a wooden dowel, and peen the metal all around it with a punch, to prevent it popping out again. You may need a new head gasket if the old one is damaged in removal.

the engine is an overhead valve twin cylinder built by Kawasaki, 18 hp liquid cooled.

Take the valve cover off and report what you find.