The Zenoah G231PUM (22.5cc) marine engine features an improved cylinder design with 4 transfer ports, high rpm piston with a thin 1.0 mm single ring design, new improved combustion chamber shape that use a compact 10 mm spark plug, large bore carburetor with manual choke plus a factory supplied velocity stack.   All these features give the new G231PUM engine better breathing and higher rpm over the older G230PUM two port engine.

The Zenoah G260PUM marine engine has the same features as the G231PUM engine and includes the same accessories but has an increased capacity of 25.4cc.

Both G231PUM and G260PUM engines use the same Drive Collets and Engine Mounts as the older G230PUM engine, so updating to these new engines is a simple task.