gtx 657x problem

[Patrick Arthur]

Hello i have seadoo gtx 657x with rebuilt motor. I test the seadoo this week end and run great for 2hour after i dont want to start but its turn and i do backfire trough carb and loss compression mag 90 pto 70. Sorry for my english im french ty

 

[eavega]

With bad compression, your first step is to pull the domes and see what is going on. Both pistons dropping to below 100 sounds suspiciously like run without sufficient oil...

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[Patrick Arthur]

ty i will check that and i think is possibiliti of crankshaft problem but im not sure