It is constant. When it comes on I throttle back and I have felt the water coming out. It doesn't seem hot, same temp as surrounding water.

This is on the 82 150 you posted about in other posts? If so the only warning on it should be overheat.

This is. If it is an overheat then why is the water coming out of the discharge cool? The last time it went off I idled back and felt the water coming out and it was cool.

I'm confused on why it only happens at WOT.

The water coming out of the pee hole comes out from where the water first enters the powerhead if IIRC on the cross-flows. It would always be cool. I would check your bypasses for the T-stats if it was mine and make sure they are opening. Also how old is the water pump impeller? A weak impeller will give low water pressure at higher RPM's and cause the bypass not to open and cool the engine off under load. When the horn is going off next time put your hand on the block and heads and see if they are hot or cool to the touch. You could have a back feed in the harness setting the buzzer off.

Thanks. I am looking to replace the impellor, I don't know how old it is. I'll look at the t-stat to see how the look.

Looked at the T-stats today. I think I found my problem. Whoever changed the last used a sh1t load of RTV silicone and mostly blocked the passages.

The pressure release valve was slightly melted. Is this release valve used to prevent overheated condition?

The T-stats open at about 160 deg, both of them. So I put them back in. I'll try to take the boat out tomorrow and check them.

The bypass is meant to open when the engine reaches roughly 3000 RPM's so that the T-stats are bypassed when the engine is running under load. @ strokers tend to need alot of heat at low RPM's to burn the fuel mixture, but under load they want to be run around 100-130 degrees to prevent a piston from sticking. The water pressure that the water pump produces is what opens the bypass on your engine, so a weak impeller will not make enough water pressure to open the bypass. Also the T-stats don't flow enough water at speed to allow the engine to run cool, so the bypasses are a requirement to allow the cooling system to function at all RPM's.

I see but the water passages in the t-stat housing were partially blocked by the RTV. Even if the bypass did open I wasn't getting good water flow around the head, no matter the impeller condition.

I'm going out later to see if there is an improvement. The impeller is next on the list. I going to change it anyway.

It might scare ya to see what that impeller looks like. Could be "not too bad", or "HOLY $&%!".