GP 1200 sometimes fast, sometime not

[Padre Paul]

I can get my ski up to 63 sometimes. Other times 45 or 50 is all it will do. I can hold about half throttle and it will be bogging down and then all of a sudden almost jump out from under me. I bought it with 130 hours and it ran fine. It now has 152 hours on it. It has a protec steering nozzle and intake grate. It also has a factory pipe. Oh yeah, those speeds are on the speedmeter which I understand is not reliable. I am a pretty good mechanic on cars but have never touched this thing except for plugs and fuel filter. Any help is appreciated.

[David3aces]

Re: GP 1200 sometimes fast, sometime not

carbs....all 3 must function well or...............

[skraggy]

Re: GP 1200 sometimes fast, sometime not

Possible fuel tank vent problem also.

[Padre Paul]

Re: GP 1200 sometimes fast, sometime not

Do the carbs almost always need to be rebuilt after 150 hours? I have ordered a block off plate and am going to premix.

How would I check a tank vent issue?

Thanks again,

[uncle-buck]

Re: GP 1200 sometimes fast, sometime not

Make sure you can only blow one way through the fuel tank check valve (no. 12 in the attached diagram). If you can blow through both ends, replace it.

And be sure and reinstall it with the arrow pointing towards the tank.

Good luck.

[Tontsa80]

Re: GP 1200 sometimes fast, sometime not

[QUOTE=uncle-buck]Make sure you can only blow one way through the fuel tank check valve (no. 12 in the attached diagram). If you can blow through both ends, replace it.

And be sure and reinstall it with the arrow pointing towards the tank.