Overheating issue
 

Any ideas:
My 96 271 - SR1 normally runs at about 180 degrees.
Took it out for the first ride last weekend and it ran fine at about 2k rpms. Once I got on it a bit I realized that the temp was on its way over 200 degrees. I backed it down and the temp came back down. Seems to only get hot at high rpm.

The impeller was replaced in Aug. of last year.

Any idea where I should look.

Embarrased to say that i cant remember if it has a strainer on it that may be clogging. Also dont know where it would be on this boat.

Ideas??

Thanks,

Josh

looking at the engine it should be on the lower right hand of the motor by the hull stringer. it will look like a long canister with two hoses . one in and one out. hope this helps . it could be on the opposite side also depending on the setup.

you might double check the impeller it could be defective and took seat over the winter. it could have ripped a couple of blades or your out drive water intakes could be plugged with sea weed.

water pump?

I had exactly this problem.
I'll bet you have limited cooling water flow.

Labor: First the easy stuff.
Backflush the outdrive. Easy: take the raw water feed off the raw water pump, stick a hose in there, and blast it back.

Clean the oil cooler. Might be harder to remove, but take it out and clean it out with rods through the cooling passages. They can get filled with rocks and junk and restrict flow.

I did all this, and it did not help. But its cheap, so do it first.

In my case, the real problem is the twisty little passages in the outdrive. These are very restrictive, and will clog dramatically with the slightest bit of corrosion. They can clog with sediment too (so maybe you'll be lucky with just back flushing the drive).

Try "offshore intakes" -- water intake tubes through the transom -- instead of trying to get water through the outdrives. You will need strainers and pressure relief valves, but then you will have flow.

Does act like an impeller, easy enough to replace. However, it also sounds like clogage. I may be wrong but, I don't think you have an actual "strainer". The inlet goes to the engine-driven water pump, then to the oil/power steering cooler. This little cooler can act like a strainer. At least it does on my older vintage 454 mags. The flow-through holes are only the size of a pencil and they can get clogged. This condition could let enough water pass to cool the engine at slower speeds but not flow enough volume at higher revs. Take the hoses off and back-flush it.

Gotta be one or the other.

thanks all. we'll see this weekend.

Sticking thermostat?

That would be one of the 1st things I would check. Actually for 10 bucks or so, I'd just put a new one in as the gaskets probably cost that much anyways to take a look.

I'm thinking no. A stuck thermostat would not respond to RPMs. It got hotter as the revs went up, cooler as the revs came down. It's a tired impeller or cloggage.