Strange things are happening.

[76papa]

On some occasions and for no apparent reason my F115 will shudder and shake the whole boat. When this happens, the temperature alarm sounds. The pump is working as evident from the **** stream. The vibration stops at below 2500 rpms. The problem can disappear as abruptly as it started.

 

[Silvertip]

Read your owners manual. The engine is going into limp home mode due to an overheat which prevents it from reving over 2500 rpm. And just because the pump is working does not mean the engine is not overheating. A healthy tell tale stream means only that the pump is working. There is a thermostat that may be sticking shut or some other engine issue causing overheating -- such as a cooling system full of sand.