99 gti engine locks (turns full revolution either way)

[frederick]

seadoo gti 720 i was cranking engine didnt start and then locked
it now turns freely one revolution either way then locks
starter had been acting up for a while and i suspect it may be jammed
has anyone had similar problem and is it poss for starter to do this or is it wishfull thinking?
any one got any ideas before i remove starter (looks a pig of a job)

 

[mikidymac]

The first step is to remove the pump as they can lock up too and you will need to do it if you have to pull the engine anyway.

It would be very uncommon to be the starter.

Make sure you undo the stainless hat on the driveshaft seal before removing the pump.