2003-2005 Kawasaki Ultra-150 Jet Ski Factory Service Manual., Page 133Get this manual
8-18 ENGINE BOTTOM END Crankcase
p on- Aalpley [a ]nandprerar acnentklockving[B]gent to the front check vv hec al Press the check valves until their flanges portions are bot tomedAt this timedo not plug up the holes of check