If you go to the MTH website and search for item -- 20-2175-1 (which is a PS1 engine - GP9 in Western Maryland), you will find a PDF download for the manual. Everything will be the same except maybe where the volume sound pod is on the bottom and maybe a switch on the bottom of the frame. Also the "how to remove the shell" will be slightly different, but all of the operating instructions will be the same as your engine.