starts and runs perfectly on the land but when launched shuts off and will not start

[Simmons]

I have a 1999 Yamaha XLT 1200 that no one can fix. It starts and runs perfectly on the land but the moment it's launched into the water it shuts off and it will not start anymore while in the water. Can anybody suggest what might be the problem? Thanks!

[Edwin_nam]

Re: starts and runs perfectly on the land but when launched shuts off and will not st

Check your compression in all cylinders

[Jet-Nut]

Re: starts and runs perfectly on the land but when launched shuts off and will not st

You will most likely find that the #3 cylinder has little or no compression.

[Simmons]

Re: starts and runs perfectly on the land but when launched shuts off and will not st

Thank you both so much. I don't understand very much about the machine, but I will pass the suggestions onto my mechanic. This is the first wave runner that he was not able to fix. He told me the compression was good but I wonder if it was on all the cylinders. What should I tell him why it could be cylinder # 3? Thanks again.