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Indmar Operating Temperature


2THEL8K

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Thought I'd reach out to the community before calling Indmar tomorrow since they are closed for the day. We have a 2000 Sunsetter VLX with an Indmar 350 (IC97) according to the manual. The manual is not in great shape from previous water damage, and that's about all I can make out. The question is with regard to the "normal" operating temperature for the engine. The impeller was recently changed, and the engine appears to be running warmer than I remember (around 170). Here are my questions:

1- Does this sound like the normal operating temp? If not, does anyone know what normal is for this engine?

2- Do these engines have a thermostat similar to a vehicle engine since the cooling system is different?

3- Assuming this temp is higher than normal, any other areas to check if there appears to be good water flow through the hoses?

Thank you

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I may have found part of the answer on the Indmar website. I downloaded the '94 - '02 manual, and it mentions normal operating temp of 120 - 140. So, it seems that 170 is high. This being the case, any suggestions as to what I should check other than the impeller to bring the temp back down?

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Is that the carb or fuel injected engine?

Shouldn't matter as both should have a 160 thermostat in them. The thermostat is at the top aft of the engine where all the hoses come together. The temp on my 01 with FI Monsoon II varies from about 160 - 165 (center of the gauge to less than 1 line above it). All hoses, thermostat and impeller are new within the last year. Others say their temp never moves from 160 once warm.

It's a little harder to see on your engine because it's in backwards :), but you could have parts of the impeller or other debris caught & partially blocking water flow at the transmission oil cooler. Should be on the starboard aft side of the engine immediately after the hose from the impeller pump. Pull off the hose from the bottom of the trans cooler (or both sides) & check to make sure the tubes in the heat exchanger are not blocked at all. Be careful when re-attaching the hoses as it's possible to collapse the openings on the trans cooler (it's copper).

Also make sure the hose from the thru-hull to the impeller don't have any leaks and the interiors is not collapsed.

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Thank you both for the replies. The boat was hauled up to Shasta today, and I'm headed up tomorrow. Just want to make sure I head up prepared to address any potential problem areas. After speaking to my Dad later this evening, he quickly identified where the thermostat is located. I think I'll bring one up just in case since it's never been changed. Checking for debris is also a good idea as I know we burned up an impeller a while back (wife didn't know about turning the boat over before it hit the water :-) ). In addition, we hit a hidden sand bar at the Delta a few weeks ago (love the Delta where seemingly wide open and obstacle free waterways have plenty of hidden surprises), so I would imagine there was potential to take in some fine debris. Nonetheless, I appreciate the information and have a few areas to check.

FYI, it is a throttle body FI engine

Edited by 2THEL8K
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If you have any issues Oasis Marine in Redding are cool dudes that are very helpful. Temp should be 160 degrees, if it's off more than 10 degrees imho I'd get it checked if the impeller and thermostat are fine.

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If the thermostat hasn't been changed, you will be in for a bit of time scraping & cleaning the mating surfaces to do it right - OK a lot of time. Took me a few hours to do it by hand with a scraper & brush.

The bolts may be corroded a bit too. I believe there are 2 - 2 1/4 x 3/8 and 1 1 1/4 by 5/16 Grade 8 holding the housing down if you want to be prepared to replace them.

If you can, get a marine thermostat and both gaskets, I believe the marine T-stat has a higher flow capacity than typical auto ones. Gaskets are quite different. Cost me about $16 for all 3 at the local dealer.

Marine Thermostat

Auto Thermostat

Edit: Fix Auto link

Edited by wienrdog
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If you have any issues Oasis Marine in Redding are cool dudes that are very helpful. Temp should be 160 degrees, if it's off more than 10 degrees imho I'd get it checked if the impeller and thermostat are fine.

Perfect, thank you. I'll give them a call this morning. If they have the parts I need, I'll stop there on my way up.

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If the thermostat hasn't been changed, you will be in for a bit of time scraping & cleaning the mating surfaces to do it right - OK a lot of time. Took me a few hours to do it by hand with a scraper & brush.

The bolts may be corroded a bit too. I believe there are 2 - 2 1/4 x 3/8 and 1 1 1/4 by 5/16 Grade 8 holding the housing down if you want to be prepared to replace them.

If you can, get a marine thermostat and both gaskets, I believe the marine T-stat has a higher flow capacity than typical auto ones. Gaskets are quite different. Cost me about $16 for all 3 at the local dealer.

Marine Thermostat

Auto Thermostat

Edit: Fix Auto link

Thank you for the details. Sounds like it's a bit time consuming, but probably something that should be done. I appreciate the suggestion on the proper tools to bring along.

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Is there a phone number for Malibu that isn't posted on their website where I can call for tech help? I could be completely missing it, but I've looked around, and the only thing I can find is an email contact form. I'm still having trouble with the engine heating up after replacing the impeller and thermostat, and after pulling a few hoses to check for blockage, good water flow, etc.

Regarding the problem, the boat temp is fine at lower RPMs, but as soon as we operate at skiing speeds, the temp shoots way up (over 200). The temp comes right back down at idle speeds (around 160), and I've pulled hoses to look at water flow, etc. I don't know if it's the water pump or something else internal to the engine (i.e. head gasket). I also don't know if the engine can somehow be backflushed to try and clear any other blockage points (water jackets was one other area suggested to me, but I have no idea what this is). At this point, I would like to talk to someone at Malibu for other suggestions before taking it down to a service shop, which is not exactly convenient from where I live. Any help would be appreciated.

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