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Revving problem

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Subjockey

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Hi,
I have just put a new piston and rings in and rebuilt the carbys on my 1996 seadoo gtx with a 787cc. It's starts up first click of the button but revs straight to 7000rpm then I immediately shut it down, when I cleaned the carbys the low jets weren't going in fully and I had to play around for a while to get them to go in fully, I'm pretty sure it was corrosion, I set them at 1 turn out, any ideas why it's idling at 7000rpm? And it's a new piston and rings so I don't want to let it go just on the hose.
Thanks in advance
 
Try and first look at the throttle and see if you can adjust it and turn it in and lower it. I had that problem on my XP I thought it was a runaway engine but I really just had the idle screw to far in
 
Yep, probably an air leak in the intake manifold like a missing screw or gasket, or you have the carb idle set too high/throttle cable is misadjusted. Also if you're using oil injection make sure to recheck/adjust the oil pump lever calibration once your done adjusting the idle.
 
Could it be a leak in the exhaust manifold, because we had some trouble getting that back on, and also the idle adjust screw is all the way out, but my throttle cable is tight no slack at all, so if I'm correct it won't take much to rev on the hose if the throttle is open a bit?
 
An exhaust leak will tend to fill the bilge with non-combustable carbon monoxide and displace air needed for combustion, so the engine will run rough and not make power as it should while on the water. I don't expect an exhaust leak will cause the engine to race. If in-water engine performance is lacking but improves by removing the seat to allow improved ventilation, then look for an exhaust leak.

This sounds much like the throttle cable connection is somehow incorrect or adjustment might be causing your issue, there should be some slight slack in the cable at idle position, approximately one or two millimeters, just enough to allow the carby throttle plates to fully close shutting off the air. Or if there's an air leak somewhere in the intake manifold piping(such as a missing or possibly torn gasket) there will also be too much air bypassing the carby throttle plates.

Keep looking, your getting close!
 
Yes.. Check throttle cable. If it holds it just a little open yes the engine will run up to 7000 rpm. DO NOT START IT UNTIL THE PROBLEM IS FIXED!! the engine will destroy itself.
 
Hi,
Sorry it took so long to reply I just got a chance to have a go at fixing it, I adjusted the throttle cable and the link age between carbies, the front one was closed and the back one was open a bit, once I fixed that and got it started, the idle was real low so I adjusted the idle screw and it idles at 3000 rpm now as the manual states. Just waiting for the jet pump rebuild kit and I'll be right to get this thing out on the water!
Without you guys helping me out with my many different problems I would not have this thing going, so thanks heaps!
 
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