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Engine Temp Monsoon


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Hoping to get some reassurance that this is fine. I just replaced the impeller on my Monsoon (2011). Was paying particular attention to the temps. The engine would hover around 160 as expected... but would range up as high as maybe 175 when we'd come off plane pulling a boarder and then settle back down to around 160. When reving the engine up to 3000 RPM from idle it would go as low as 140. It did always pretty much center again at 160 pretty quickly. I seem to always remember the temp being around 160... but I guess I never really paid attention to it all the time before... so it could have done this before. Does this sound like a pretty normal operating cycle/temp range for the Monsoon? I'm fairly novice when it comes to engine mechanics... so just trying to learn something. Does the system actively change the amount of water that is sucked in to keep the temp constant... or is it simply a matter of "when the engine spins faster the impeller spins faster". The gas that is being run is mostly stabilized stuff from 6 months ago. Could that cause the temps to spike up a little higher? Thanks all!

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Seems like your thermostat could be sticking a little... It's not unusual for the temp to move a 5 degrees or so, but 15 - 20 is more than normal.

The thermostat is what controls the cool water flow into the engine (really lets hot water out to be replaced by cool water). The impeller/raw water pump will always move the same amount of water, but if the thermostat is closed, the cool water will bypass the engine & go straight out the exhaust.

With the very cool lake water this early, the temps may move a little more than mid-summer.

Edited by wienrdog
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Did you replace the impellar because the old one went bad? If yes, I'm wondering if there might be an old impellar piece stuck at the tranny cooler?

All is probably ok, but wondering because I know your and my water temps are still very cool. Where did you go? Jealous.

Steve B.

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Did you replace the impellar because the old one went bad? If yes, I'm wondering if there might be an old impellar piece stuck at the tranny cooler?

All is probably ok, but wondering because I know your and my water temps are still very cool. Where did you go? Jealous.

Steve B.

Steve,

I replaced it just for a routine spring maintenance. The old one looked to be in pretty good condition with no pieces missing. Housing also seemed fine. The water temp was actually 68 on Portage lake! Amazing for March 24. We just took a couple quick runs on Turkeyfoot on Saturday. When you going to get your boat out?

Troy

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Steve,

I replaced it just for a routine spring maintenance. The old one looked to be in pretty good condition with no pieces missing. Housing also seemed fine. The water temp was actually 68 on Portage lake! Amazing for March 24. We just took a couple quick runs on Turkeyfoot on Saturday. When you going to get your boat out?

Troy

As soon as it warms up again Troy ! I'll PM you and see if we can do a ski get-together !

Steve B.

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Seems like your thermostat could be sticking a little... It's not unusual for the temp to move a 5 degrees or so, but 15 - 20 is more than normal.

The thermostat is what controls the cool water flow into the engine (really lets hot water out to be replaced by cool water). The impeller/raw water pump will always move the same amount of water, but if the thermostat is closed, the cool water will bypass the engine & go straight out the exhaust.

With the very cool lake water this early, the temps may move a little more than mid-summer.

Is the thermostat sticking something that could have been affected when they winterized it? Or have something to do with taking one of the hoses off during that process?

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Seems like your thermostat could be sticking a little... It's not unusual for the temp to move a 5 degrees or so, but 15 - 20 is more than normal.

The thermostat is what controls the cool water flow into the engine (really lets hot water out to be replaced by cool water). The impeller/raw water pump will always move the same amount of water, but if the thermostat is closed, the cool water will bypass the engine & go straight out the exhaust.

With the very cool lake water this early, the temps may move a little more than mid-summer.

I had to look up where Maineville was! Should have just asked my wife since she grew up in Blue Ash right next door.

Since you're in Ohio you should join us for the WOW at Salt Fork in July. Had about 8-10 Bu's there last year... hopefully more this year!

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I had to look up where Maineville was! Should have just asked my wife since she grew up in Blue Ash right next door.

Since you're in Ohio you should join us for the WOW at Salt Fork in July. Had about 8-10 Bu's there last year... hopefully more this year!

I'll try to make the WOW too Troy. My problem is I'm taking time off the week of the 4th too. We'll see if I can get out of work then also.

Steve B.

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  • 2 weeks later...

So I might have found the cause of my temp issues. There was a leak in the impeller gasket. I pulled the cover off and a 1 cm chunk was missing. I think i didn't put it on centered... and I didn't screw it down right (tighted each nut completely one at a time.... probably a dumb rookie mistake). So this time I just kept going around the circle tightening each one about a 1/4 turn or so so the gasket laid down evenly. Water test tomorrow. Hope it was just a problem of an air leak. Is it worthwhile fishing downstream for a 1 cm chunk of gasket?

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If you ignored the 1 cm piece of gasket, you would most likely be fine. But, as an excuse to work on the boat, I would check the transmission fluid cooler. It is simple and quick to do, and you might also find weeds or other debris in there too. If you're not familiar with that, follow the water hose from the raw water pump to the next connection point. It will be a cylindrical part with two large diameter water lines running out of the ends and two smaller diamter transmission fluid lines connecting in the middle. Remove the large diameter water hose from the raw water pump itself and the raw water pump side of the tranny cooler and clean out the hose. Look up inside the tranny cooer and you should see a screen. Make sure that it clear, and you are good. When I did this to my boat just for fun I pulled about a cup of weeds, plastic bag bits, and impeller chunks out (and my monsoon wasn't even having temp issues).

You have a beautifut boat. Enjoy caring for it and have fun!

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Water test today Troy? Dude you are hardcore !! (compliment :)) For piece of mind, I think I'd look at the next place downstream of the pump. Is the tranny cooler on yours before or after the pump? After you get piece of mind, drive it like you stole it !

Steve

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Water test today Troy? Dude you are hardcore !! (compliment :)) For piece of mind, I think I'd look at the next place downstream of the pump. Is the tranny cooler on yours before or after the pump? After you get piece of mind, drive it like you stole it !

Steve

I'll look tonight at the next step along the path of the water cooling system.

Probable water test today... maybe tomorrow. I'd go skiing today if I could find a couple people crazy enough to go!

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So I might have found the cause of my temp issues. There was a leak in the impeller gasket. I pulled the cover off and a 1 cm chunk was missing. I think i didn't put it on centered... and I didn't screw it down right (tighted each nut completely one at a time.... probably a dumb rookie mistake). So this time I just kept going around the circle tightening each one about a 1/4 turn or so so the gasket laid down evenly. Water test tomorrow. Hope it was just a problem of an air leak. Is it worthwhile fishing downstream for a 1 cm chunk of gasket?

Not to worry about the 1 cm peice of gasket. I got "burned" in a simialr manner when I changed my impeller and did not change the gasket. Temp would fluctate, pump would not prime thus no water circulation. Now I change the gasket every time I replace the impeller.

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Water tested today after putting the gasket on again (the right way). Temp was solid... ranged between 150 and 170 on rare occasion. Monsoon was purring. Must have been the seal on the impeller. Ready for a great summer!

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Just curious...does your boat have a heater on on it?

Yep. It was turned on once the first time I went out this year. Did not turn the heater on the second time or today after changing the gasket.

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I'm not sure how valid my observation is, but from what I seen it seems when a heater is installed with the y fitting for the return line the engine temp is a litle more unstable vs the return line being routed back into the engine's water pump. Just something I noticed...I will find and put up some pictures of a modification.

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i think your temp issues are within a normal range. I bought my 2000 last year and i was concerned with the temp because it would go from 160-180...when it hit 175-180 it would quickly go back down to 160...never below 160 but never above 180. I talked to my local mechanics and they said no worries.....but make sure you dont get higher. Maybe be a little corrosion in the thermo housing

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