PEVO

Iv'e got a 2000 STX900 w/a locked up engine(bought it that way), i was told that they thought it locked up due to a injection pump failure. I have yet to tear it down...what could all be toasted in the engine? Oh well, i just picked up a running STX 1997 900 engine for cheap. Will this one drop right in or do i need to switch out the intake/carbs from the 2000 to the 97 engine. Also i'm considering going to premix. thanks

John WCSS

The actual engine block will drop right in. You may have a different pulse line(things that run the fuel pumps on the carbs) set up.Before you put either engine in and run it you should clean or rebuild the carbs,check all the fuel lines , and replace any filters. Also you should drain the fuel out and start with fresh.

tfergusonracing

Pull the bad engine first and make sure that's what's locked up. It could be that the pump is locked.

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PEVO

Well nothing beats a physical teardown inspection. Boy i'm thinking this motor has had it. First, worst & formost the piston in the center looks like a grey lump of coal It got so hot that the top most ring is almost totally exposed(piston edges flaked off in big chunks) also the sides of the piston cracked apart. This cylinder is scared to hell. Parts of the piston are caught up in the crank stopping it from 360 degree motion. The rod bearing(on the crank) is wallowed out & discolored. The other 2 cylinders don't look near as bad w #1 piston having a slight ding it it(i'm assuming from detonation? Also both other pistions show abnormal ware on the sides(4 corners). However the front & rear rods look good. What could have caused this? Oiler not working as i first figured??? Any comments welcome

PEVO

Update on the swap. ie. 97 900 engine replacing a blown 900 in a 2000stx. The basic case, cylinders-head are the same. But the carbs are different. I went with the CVs so i had to swap intake too. Also the stator wiring harness is different...so another swap. The exhaust is different too...so Another swap there. The PTO?...yep it's different too,...so another swap along with the PTO cover. Oh & don't forget the motor mounts/engine plate....swap too. The older engine had two pulse fittings vs the one on the 2000...no biggie there. It was about like a longblock exchange...almost everything from the blowed engine refitting to the older running engine.