Thread:

Please don't kill me

I know there have been a ton of over heating threads so I'm hoping y'all won't murder for starting another one.

The situation: My buddy just bought an 89 Carrera with a supposedly rebuilt pump ( according to the previous owner). We took it out a couple weeks ago and it over heats at idle and low RPM's. I mean pegged on the gauge. As soon as he gets up to speed it cools back down.

What we have done so far: yesterday we took the thermostat housing apart, no t-stat. Checked the plumbing (logs with snails) plumbed correctly. Checked all plumbing for any blockage and found none. Pulled the plugs and they are fine. No water in the oil. Ran it on the hose for approx 15-20 minutes and she was as cool as a cucumber.

My question's: Would there be any reason the pump isn't moving enough water at lower RPM's? Could timing be the culprit? We haven't checked it yet.

Any advice and help would be much appreciated.

Here's a couple pics I took. Maybe I'm missing something.

Is the gauge working? Did you guys get a freezer thermo, to check temp of out going water?

No. But we did have a laser thermometer when we ran it in the driveway and it is corresponding with the gauge. I know that doesn't mean it's working right all the time.

You said freezer thermometer? I'm confused. Teach me.

Thanks Tom. I'm not sure what the RPM's are at W.O.T. Or what it feels like as when I went to drive it the reverse cable broke and we spent my drive time rigging the bucket op. Im not sure if he would be able to tell the difference but he passed me like I was sitting still in my tank. The impeller has a couple dings in it but nothing too serious but we haven't taken anything apart yet. It seems to do ok but I'll have to ask him.

What would we be looking for?

A friend of mine had the same problem. A couple fittings IDs were too small. Replaced the fittings and the problem was fixed.

I had this problem at the river and all it turned out being was somehow my gate valve onthe inlet from the pump was turned down 1 1/2 turns down. I closed it and recounted my turns and all has been good. I hope your problem is as simple

Originally Posted by brgrcru

Is the gauge working? Did you guys get a freezer thermo, to check temp of out going water?

This might be a rookie question, but the outgoing water leaves the boat through the exhaust, or somewhere else?

Depends on the exhaust. If you have o.t. Headers then most of the water leaves through the transom of the boat with a little water going through the exhaust for cooling. If you have logs the all the water should exit through the exhaust.

Thanks for the input guys. When my buddy bought the boat there was no gate valve on the pump and I didn't catch it until we were already on the water. I think we will change all the fittings especially the one coming off the pump and see what happens. If we still have the same issue I'll start looking into the pump.

One more thing is change all the inlet and outlet hoses, It costs next to nothing. I had a hose come apart inside and it developed a flapper that had no effect when running ,but at idle it acted like a check valve blocking water flow

Will do!

Next time its in the water pull a few hoses and check flow. If it's overheating, something is plugged up. By pulling hoses and checking flow, you'll find the weak spot... Like Tom said, they don't usually run hot...