Carbs or fuel pump?

[Henrydo]

Hey guys, I'm new to this forum.
I recently had bought a 2001 seadoo gti. I took it out a few times, it was ridding perfect. Up until 4 days ago I was riding and I started to notice I wasn't moving as fast. My jet ski slowed down a lot. Then it started to surge it would go fast then Slow down then fast and kept on doing that. Then it ended up dying on me and it wouldn't start. I got the jet ski home, changed the spark plugs wouldn't start either then I took I sprayed some carb cleaner in carbs and then it eventually started. Took the jet ski out again rides fine for the first 10 mins then it will start to surge. If I keep on holding the throttle down eventually it will shut off but now it starts right back and it will idle all day long and not turn off . Only when i am giving it full throttle. Also when I give it full throttle out of water it back fires. What could be the issues here? Carbs or fuel pump? Checked compression too 145/145 in both cylinder.
Any little help would be appreciated.

Thanks,
Henry

[raiderteen]

A 2001 GTI has one carb with an internal fuel filter. Might as well rebuild the carb with a genuine mikuni rebuild kit as it also includes the fuel pump parts.

While you are working on it, if the fuel lines are still the factory grey "tempo" fuel lines you need to replace them with a 1/4" fuel hose of your choice. I use Gates rubber fuel hose found at O'Reilly's. The grey fuel lines are known for corroding from the inside and clogging the internal fuel filter inside the carb. Clean out the fuel/water separator as well.

Then last thing to check is your fuel tank vent check valves. One lets air in (the higher mounted one on the hull) and one lets air out past a few psi of positive pressure (mounted just above waterline on right front of ski). The one that lets air out keeps a small amount of positive pressure in the tank.