01 GP1200r just quit at 45mph

[Bamaboy1325]

I need plenty of advice as I'm pretty stupid when it comes to troubleshooting. We've been running the ski for two days hard. My cousin went to fill it up at the marina and on the way back to the camp it cut off while running 45mph. No spit and sputter or nothing. A warning came on but he didn't know to look and see what it said. Wouldn't crank back up and had to get towed back. I was trying to crank it after he got back and got the seat off and it sounds like the engine is under pressure. It even blew a big burst of air out the back almost like a backfire. I haven't had it but a few months and the only mods I've done is the d plate and chip thanks to some knowledgeable folks on here. I'm hoping someone can give me an idea of what may be wrong here. I'm open to trying anything cause it's still in the water. Thanks

[Robfromga]

Check the compression.

[Bamaboy1325]

Compression seems fine the best I can check.

[Bamaboy1325]

It almost cranks. Right when it's about to catch up it backfires and quits.

[Robfromga]

What numbers are you getting?

[Prism]

What do the sparkplugs look like or have you not removed them due to your location? When you removed the seat was there any water in the hull? From your description it sounds like it may have sucked up water and hydrolocked which in turn broke a reed. As mentioned before, I would check the compression with a gauge when you can. Let us know what you find.

[Bamaboy1325]

I don't have a gauge of any sort but we have pulled the plugs and bumped the engine. All three plugs look ok and have compression just by feeling. We got it to bust off on the trailer using the adaptor to run water through it. I felt comfortable so we took it back to the boat ramp. Crank up and idled out to the wake sign, hammered on it and it got to about 50 then I felt it loosing power. Same thing but it didn't throw a warning this time. Just cut off. There is no water in the hull. I'm at a loss now. Any help is welcome

[Robfromga]

You need a compression tester.
Stop running it until you check the compression. It should be 120ish and all 3 should be the same or within 1-2 psi

[wavedude]

Burst of air out the back sounds like a rear seal blew. Got to get compression #s before you run it again.

[Bamaboy1325]

I've got it packed up for the weekend. Thanks for the advice. I'll check the compression when I get home.