Can I drop a small car motor into my sea doo jet boat instead of the stock 787? How much trouble would it be?

Question

96 sea doo challenger. Everything there but the motor itself.

Answer 1

take into consideration---how you gonna hook it up to the jet drive?---how you gonna keep it cool from over heating-?---also exhaust set up---controls for the gas throttle---electrical hook ups to keep the batterry charged---last but not least weight---will it be top heavy a wanna roll over on turns?---but if it could be done a small v-6 might be sweet--no much sense in using a 4 cylinder --the two stroke you have in there now should out rev and out power any 4 cylinder---a small motorcycle engine could be more easier done---like a 4 cylinder air cooled or 6 cylinder air cooled engine---make sure you have vents for air if you go with air cooled--

Answer 2

If you can fabricate the needed engine mounts and there is enough clearance for the motor to fit, it should work OK.  You are limited by your skill level and how much money you want to spend.

The one downside that you may run into is the pitch on the impeller that runs the jet.  If the car engine runs as the same RPM range as the old engine, then all is well, if it is a lower RPM engine, then you would either need a gear box to up the RPM's or a new Impeller for that speed range...

Sounds like a fun project to tackle though, would be a blast to drive around!  

Good luck...