Engine running hot after impeller change

[ScarletArrow]

Hoping someone can direct me...

Put 200 in the water for the first time this year yesterday... engine started running hot 200+*.

Checked the thermostat and impeller - obvious problem, Impeller was bad.

Local MC dealer who sold us the parts also sold us new thermo that was Indmar brand.

After changing both the impeller and thermostat, engine still ran at 175*, plus started making a "gurgling" sound.

At first we thought it was pieces of the old impeller, but after checking all the hoses, we found nothing.

After about 6 passes, the "service" and "check engine" lights would flash and the boat would seem to want to go into limp mode, even though the temp gauge was static at 175.

We put the old thermostat back on and the temperature dropped to 160*, but (another symptom) the heater doesn't seem to put out any hot air.

Theory is that the motor is sucking air from somewhere, most likely the strainer at the rear of the engine where the o-ring seems to not be giving a tight seal.

Anyone experience with this or have thoughts?

Thanks in advance.

[Zach@n3]

You just have to cover the entire system front to rear. MC probably sold you a T stat for a closed loop cooling system.

[jasper]

Sounds like it is sucking air from somewhere. Check all clamps on hoses for cooling system, seal on water strainer, etc. Some have forgotten the gasket and/or o-ring in the impeller housing.

[Lakejackson]

I am pretty sure there are thermostats that open at different temps. If you get one I that opens at a different temp than the original it will make the boat run hot. If the old impeller was shredded, is it possible a small piece is stuck in the heater coil?


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