wetjet 300 problems

[pineyboy]

Last year I bought two Mastercraft Wetjets (with Yamaha 701 engines in them) that had been sitting in a garage for 8yrs. I changed the fuel and put new batteries on them and they started up and ran great. After going to he lake 5 or 6 times one of them got to where it would die when running WOT. It would start right back up and idle fine. If you let it sit for a few minutes it would run good for a little while and start doing it again. After a few more times at the lake the other one started doing the exact same thing. I stored them for the winter and early spring I took them to a so-called mech. he cleaned the carbs and fuel tank and said they were fine now. The first time I took them to the lake, same thing. I changed all the fuel lines, put new fuel filters on them, and had a friend help me put a carb kit in one of them. Took it to the lake; no better. When you go to the lake they both run great for the first 15 mins. or so. I don't think they are getting hot. I can hold my hand on the exhaust manifold.

[vdubspeed]

Lean seizing?