2009 yamaha 50hp 4 stroke bought early last year and ran great all year. This year we took it to get a tune up including replacing the impeller. The boat ran fine on its first trip out after the tune up, but at the end of the 2nd trip it stopped spitting water and the alarm came on. When turning off the engine and waiting a bit before turning back on, it would drizzle and pump sometimes, just enough for us to make our way back home very slowly.

I took the boat back to the guy who did the tune up and he flushed the pipes and said it ran fine.. Went back out on the water and it pumped hard and strong at *****ing speed but after about 5-10 min going higher speed it slowed down to a drizzle and stopped with the alarm sounding again and smoke coming out.

Took it to a yamaha dealer/mechanic this time and he said our thermostat was in bad shape and that could be it so he had it replaced. We thought maybe the impeller might have been installed wrong or something but he was sure that it wasn't it and said it'd be a waste of our money to have it checked. They ran the boat for an hour and said it looked fine.. But they were only able to run it with ear muffs on and not at full throttle.

Just took the boat out this morning and same old story. *****ed fine with a strong piss line but at higher speed it drizzled to a stop. We don't know much about fixing motors ourselves yet but taking it to the mechanics seems to just be a waste of time and money. Any suggestions would be greatly appreciated.