It would be hard to say unless we knew what was taken of for the rebuild. Usually you would have to put back the starter, the flywheel, the balancer on the crank, the oil pump, the carbs, the rave valves, etc.. I just took mine out the piston rod Bering shredded and all the pins ended up on the bottom of the crank. Did bottom end and top end. Bored over .5 . New crank, new pistons, new rings, rebuild carbs, new throttle cable. It runs like a scolded dog now. Couple of things that I learned from this forum and have been invaluable. Use oem parts, use the right rebuild kit for the carbs, print the shop manual for torque specs, use blue lock tite on EVERYTHING, or you will find bolts in your hull. Or even worst in your engine. Use the right injection oil. RENT OR BUY the engine alignment tool or you will vibrate the new engine to pieces. BUY the curved wrench to remove and install the exhaust or you will drive yourself nuts. Tune the carbs and you should be ready to go