so ive got this 98 gtx rotax 787 that i was told was over heating after a rebuild last year due to a water lock. I am also told the motor has a new oil pump. I took apart and cleaned the impeller from any debris I found, I also blew air threw all of the lines that go back there. Start it up with the hose hooked up and it idles just fine, for as long as I want...ran last night at 77 degrees. So today I took it out to the lake and ran around for not even five minutes (this was the original complaint when it was brought to me) and it just cuts out. dead. I checked the engine temp right when it died and the digital gauge said 80 degrees. I checked the plugs they are not ngk which im told is recommended, but they are resistor plugs. Also before I went out to the lake I stopped and got a new battery (the owners had a serviceable battery in it that was completely dry) I did this wondering if it was a charging/ignition problem. But now that Ive seen it die and tried to start it only to find out it locked the motor up in my mind I think its an oil problem. Im wondering if this is common? Faulty oil pump? Air in the lines? Clogged filter? Ive never worked on the oil systems before infact as far as ive gone with PWCs before now is removing exhaust systems and welding cracks from sitting over the winter and Im not even sure the oil system is my problem....any advice?...I pulled the plugs and sprayed some WD40 in the cylinders to let it sit over night and hopefully the starter can free the motor up but we'll see about that tomorrow. Also the owner is not sure that its running synthetic oil (correct me if im wrong but isnt synthetic a necessity?) Anyways I plan to change the oil and the filter is there a procedure to follow in order to get ALL of the old oil out and get the new in? Any help would be very much appreciated.
98 gtx locking up?
- Thread starter erikj04
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Erik....waaaay too common of a problem is failure with the oil injection systems. Try running premix with a 50:1 ratio (40:1 works also) of SeaDoo oil, and also do a compression test. A compression test will help let us know if this is damaging the engine and the main cuplret of the problem.
Hi and welome, Yes run it with Seadoo oil only.
You say it used to lock up and there was cracks in the exhaust system.
I would go for a new exhaust system, as the welding might not be up to it.
and leaking water into the manifold. ( not questioning the quality of the weld)
But it might have warped the contact surfaces.
And the exhaust manifold gasket not being up to the job, which would cause
back preasure. It could be stopping the water coolant getting to the vital parts, causing the overheating.
But on the hose its doing the job getting to the engine. Water preasure being high.
Just a thought, hope this helps.
You say it used to lock up and there was cracks in the exhaust system.
I would go for a new exhaust system, as the welding might not be up to it.
and leaking water into the manifold. ( not questioning the quality of the weld)
But it might have warped the contact surfaces.
And the exhaust manifold gasket not being up to the job, which would cause
back preasure. It could be stopping the water coolant getting to the vital parts, causing the overheating.
But on the hose its doing the job getting to the engine. Water preasure being high.
Just a thought, hope this helps.
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