Water Pump Operation

[buddyearl]

I have a 1966 80hp Evinrude Starflite. It has good water flow from water pump until I go 3/4 to full throttle. I'm suspecting bad impeller? Any help is appreciated.

 

[Bosunsmate]

Thats the best place to start, another thing is to check the motor isnt installed too high on the transom

 

[Chris1956]

How do you know the water flow is good at low RPM, and tapers off at high RPM? That motor has a spitter (no telltale) on it, right?

 

[buddyearl]

Water comes out good from the exhaust relief boot at lower speeds. Just spits at higher speeds. Does most of the water come out with the exhaust from the exhaust outlet? After running engine hard I can touch both sides of the block. It's hot but not hot enough to burn.

 

[F_R]

If you are unsure about the impeller, you should replace it whether it needs it or not. Trying to determine if it is ok at the moment is futile. It can fail at any time, and when it does, it's the end of the game. Knowing you have a good, fresh pump is the best defense against overheating and destruction..