03 22v engine temp stays too low 350 Mag MPI Tow

[wnytige]

We have an odd problem with our 2003 22v with the motor temp staying too low.
At the end of last year we noticed that the engine temps would hover about 120 degrees F.
Occasionally, it would jump to about 150 and then drop back down.
As it was the end of the year and the water temps were in the 40s (we are in the northeast).

This year when we put the boat in, we noticed that the temp still showed as very low.
I changed out the thermostat, but couldn't find the 170f version and installed the 160f.
The indicated temperature is staying about 120f regardless of RPM or how long the engine has been running.
At first I thought that it might be the sender or the gauge, but the engine compartment is still cool.
Usually, the engine compartment is very warm and the motor feel hot.
We also have the heater option installed and there is very little warm air coming out.

The impeller is new, the thermostat is new, the oil cooler is not clogged.
Yes... I know.. if any of the above was bad there would be an over temperature alert.


I'm at a complete loss to resolve this.
Any help is greatly appreciated.

Thanks!!!

[dom w. forte]

I would pull the thermstat housing back up and see if there is a rot hole allowing the water to by pass the stat and exit the exhaust.

[wnytige]

I'll pull it in the next few days and take some photos.
I'm not sure I'd know if there was a failure.
I tried looking online for a good photo, but didn't see one.

[wnytige]

I am on my way back down to the boat tonight to re-replace the thermostat, put in a new upper and base gasket and check to see if there is any obvious way that water is flowing past thermostat. I also wanted to confirm that I have the thermostat installed in the correct orientation but can't tell from the online pictures. Can someone describe or include a photo of the right direction it should be installed?

I can tell you first hand that having a motor that won't warm up really hurts the performance and fuel consumption.
I've also read that it may be bad for the motor in the long run as it dumps way too much fuel into the engine.

Thanks!!!

[wnytige]

Well... I finally made it down to the boat to work on the lack of heat issue and do some other maintenance.
When I took the thermostat housing off I found that the (stupid) plastic sleeve that holds the thermostat in place was missing a piece.
The piece that was missing allowed the thermostat to pop up and out of its seat.
I'm hoping that the unrestricted flow of cold water is because of that.
I had already ordered a replacement thermostat and both gaskets.
Oddly enough, when I was looking at the parts online I considered ordering a sleeve (part # 23-806922) but didn't because it was in good shape.
I can't believe that I was foolish enough to NOT spend the $10 to have a spare as I'm always ordering too much stuff.
Now I have two on order and after a bunch of calls in the area I found one in stock and picked it up during lunch.
Yup..... I will be the proud owner of three by the end of the week.
Weather dependent, I'll be down to the slip tonight to put it in.

On the plus side, I:
- Replaced the impeller
- Replaced the fuel filter (because it really sucks to pull the water pump with it in LOL)
- Changed the oil and filter
- Replaced the transmission oil (I think the tranny may be slipping and the dipstick plug and nut are missing in action)
- Put the new/current registration sticker on the hull
- Cleaned out the oil cooler

I'll follow up with photos of the two sleeves for anyone who needs it as a reference.

[wnytige]

Very exciting news for us!!!
I got back down to the slip today to put the parts in.
The parts replaced were:
- Thermostat base gasket
- Thermostat internal gasket
- Thermostat
- Plastic sleeve

The boat now comes up to normal operating temperatures and the aux heater has good output again.
The heater part makes the girls happy... so now everyone should be warm, dry and happy.


I'm attaching some photos of the sleeves in case anyone else has the same problem.
I never did find the small broken piece, I even borrowed an inspection camera and looked around, but didn't see anything.

new-sleeve.jpgold-sleeve.jpgtemp-gauge.jpg

[jgdethloff]

Thank you for posting this. I am having the same problem and the same plastic piece is missing from my sleeve. I replaced the thermostat and gaskets but the parts store did not have a new sleeve!! I'm ordering one now��

[lee]

http://marineenginedepot.com/MP/Mari...-Water-Cooled/

[wnytige]

I'm glad it helped.
I still have 2 spares as I'm sure that it will happen again, or I'll break it when taking it out.
Enjoy your summer!!