Thermostat Falure and Overheating Raptor Engine

[Tommy2slow]

Still haven’t solved my overheating issue. Replaced both the fresh water impeller and the thermostat. Not sure where to go now. After replacing the thermostat and topping up the coolant, I brought the engine up to temperature, it shot right past 160 and I shut it down at 180. At around 160 I expected to see the coolant reservoir level to drop, as I am suspecting that I still need to add more coolant, but it didn’t go down. Anybody have any ideas what might be happening?

[Zog]

Could your heat exchanger be plugged? We were having issues with a separate boat and found impeller pieces in the exchanger, resulting in the over temperature issues due to low water flow.

[Tommy2slow]

Not sure, the impeller that I removed was in perfect condition.

[Tommy2slow]

That large hose that comes ofF the thermostat housing is not hard or warm when the engine is up to temperature. I replaced the thermostat and no improvement.

[HFarr]

I had what Zog had happen in my old boat, too. But if your impeller was fine, maybe it sucked up something else, or possibly just corrosion or some other buildup that needs backflushing to get out.

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[Holdmybeer]

I can fix this for you.

I had the same issue and had to MacGyver it on the water.

From the top of the coolant reservior there is a small 1/4" hose.
Remove it at the reservoir and insert a small funnel and fill with coolant.
It will take forever but mine took 3/4 gallon of premix.
Once full, reconnect to reservoir.
Start the boat and watch Temps. It should burp air now.
Top off the reservior as needed.
Engine should stay cool on fake a lake.

FYI...this procedure is straight from the Indmar manual.

[Holdmybeer]

Tommy,
You ever get your overheating issue resolved?

[RUGER761]

Not sure, the impeller that I removed was in perfect condition.

Sorry kind of late on this one. Don't keep adding straight coolant to it, add distilled water. The coolant they use is very particular on the concentration, too high it will overheat in an instant, and of course too low it will freeze.

[Tommy2slow]

Thanks for the coolant advice, I added a 50/50 premix, but always good to remind the members. That coolant is super pricey btw! Could only find one supplier in my small town and it is almost $100/gallon (for premix!!!).

Haven’t resolved the issue yet. I tapped out, parked it for the season, and booked an appointment for next week with a local shop that does my winterizations.

I spoke with the service department for the Skiers dealer in BC, where I bought the boat, and they suspect the heater system. Apparently they are prone to vapour lock.

I will provide an update after I get it back from the dealer.


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