Four Winns I/O over heating, not pulling in lake water? this is a 1999 5.7 GSI?

Question

First outing of the season, put the boat in the water and started it , backed up and let it idle, no temp indication on gauge. Put it in gear and went about 100 yards and temp quickly went to red line. shut it down and had it towed back to the dock. I feel sure it is not pulling in any lake water, is this the impeller that performes that function? There is a device attached to the front harmonic ballancer that has two hoses on it. one appears to come from the outdrive and the other goes to the intake manifold. I'm an automotive tech and am not familiar with this type of cooling system. If your familiar, please explain.

Answer 1

The first thing i would check is the impeller. They are made of rubber and without any lubrication(water) they can burn up pretty fast.Did you start the motor out of water without bunny ears? If so i would check that first. Also,there may be some blockage somewhere in your cooling system. Sometimes insects like to make homes in the water intake holes.

Answer 2

Yep, it's the impeller in the lower unit of the outdrive.

No don't rebuild. It is a $20 part, replace it.

Answer 3

What type of outdrive do you have? I had the same problem and it was the impellar in the outdrive. Detailed directions are available online, just need to know the model of the outdrive (alpha, bravo). It also sounds as if you might have a raw water pump that could also be bad. Do you have a heat exchanger?(looks like a small barrel with a radiator cap)