88 70hp Yamaha Lost of power

[minnfish]

I have a 88 70hp 2 stroke. I was running all week in Canada and on the last day at full power it lost power and would only Tac at about 2300rpm.
In (N) using the cold start lever I could get the RPMs up to 5,000 easy.
It rained heavy on my morning trip (same day) while running. Starts fine, idle is ok. Could it be fouled plugs, water in carbs or fuel? Would this cause my problem? I have not used since. 7/12/11
Anyone? Thanks.

[boats.net]

It could be anything you mentioned as well as low compression, dirty carbs, fuel restriction or an ignition problem. run compression test, test spark at plugs, have fuel sytem vacumn and pressure test done on it.