Adding A Water Temp Sensor on 1990 Force 90

Derrick Fronckowiak

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Gents (and Ladies), I want to install a temp gage sender (for a gage) on my 1990 Force 90. I already have the sensor for the over temp buzzer installed (and sealed) on the middle of the head (comes that way from the factory I believe. Is it possible (or even advisable) to install a temp gage sensor on the top of the head above the thermostat where that little slotted plug is, or would it have to be installed in place of the over temp sensor on the middle of the head?
 

jerryjerry05

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The little slotted plug is where it goes.
Good luck getting it out.
Heat and ice.
 

Derrick Fronckowiak

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JerryJerry, sage wisdom...as always. For some reason, I thought that plug gets removed if you are wanting to install a tell tale fitting. I was just concerned whether or not it will give a good sensing point to provide a good representative temperature indication (since it's mounted on the top of the head instead of the middle where the over temp sender is). I'll try some penetrating oil followed by maybe a torch (see if the expansion and contract will get that plug out). Thanks.
 

jerryjerry05

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Some of the other older Chryslers had the temp sending unit right where that plug is.
If you look inside the space at the top where the thermo fits.
You'll see there is a cavity that the sensor will fit right into.
The water gets as hot at the top as it does in the mid section.
Now if your block is clogged from sand or crud? the temps can vary do to the amount of clog.

If I think it's getting warmer than it should?? I use a heat gun and make sure.
 

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Derrick Fronckowiak

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JerryJerry, Thanks for the advice (yet again) and for the picture you provided. Heat gun sounds safer and better control of the temp as well. Now you've really got me wondering about what the water jackets look like inside my motor, mine is a 1990 and I've never pulled the head off. I had started using Salt Terminator to flush my motor out last spring/summer. But do you think that stuff can/will remove salt that's built up on an older motor like mine and like the one you have in the picture you sent? Is there another more "heavy duty" way to flush out a motor if you think you have salt/crud build up inside or is disassembly and scraping the only way? Thoughts?
 

jerryjerry05

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There is NO cleaner that can dissolve the hard build up that's shown in my pics.
I used a screwdriver and a ice pick.

One quick check is to remove the thermostat and see how much corrosion/crud is built up on it.
Post a pic.
 

Sea Rider

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Installing a heat temp gauge is useless, if engine overheats severely say when lower leg water intakes are clogged, thermo is in bad shape while at speed will see temp needle skyrocketing to max temp. Temp rises extremely fast. For engine protection need to have heat sensors doing their homework right for engine going to idle speed when an overheat is detected.

Spray an oversose of pure vinegar in all water passages, let penetrate, remove crusts with a wooden shushi stick and hand power, repeat process if needed..

Happy Boatinge
 
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jerryjerry05

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I always thought the overheat warning system on ALL boats was severely lacking.
They put a $.50 buzzer under the dash and expect you to hear it at cruising speed????

I always recommended putting a car/motorcycle horn in place of the cheapo buzzer.
And put it someplace where it can be heard.
A light that would flash on the dash or even a pressure gauge with a light would be better.

Most don't know what the horn means WHEN it does go off!!! :)
 

Derrick Fronckowiak

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I was in Puget Sound a few years ago and was going through an inlet where a lot of kelp grows. I had unwittingly drove right through the kelp bed and needless to say a bunch of it wrapped around the lower leg of my motor and blocked the water inlet. I was cruising at mid-throttle range at the time and the warning buzzer went off. I barely heard it and had to put my head down closer to the dash just to make sure I heard what I thought I heard. Of course I secured the engine immediately and let it cool down (used my kicker motor to make progress through the inlet and buy time for the main motor to cool down). But, JerryJerry you are right, that buzzer is barely audible. I was only at about half throttle when it went off, if I'd had it at WOT between the engine noise and the wind rushing noise I probably wouldn't have heard it until it was too late.

Sea Rider, thanks for your advice. When I go to put in the temp gage sensor I'll pull the thermostat and see if I can see a bunch of crud built up inside. If it looks bad, I'll pull the head and maybe try your vinegar idea.
 

Derrick Fronckowiak

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Also, Jerry Jerry your idea about a warning light in the dash seems simple enough to do. could just wire it in parallel with the buzzer.
 

Sea Rider

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I When I go to put in the temp gage sensor I'll pull the thermostat and see if I can see a bunch of crud built up inside. If it looks bad, I'll pull the head and maybe try your vinegar idea.

Before tearing powerhead down to clean all water passages, there's a product called Salt Away that cleans salt formations in water passages, use it as suggested, thermo is other story, if severely rusted install a new one, if only slightly salt crusted, inmerse thermo in pure vinegar for at least one hour and brush salt off with a hard bristle toothbrush.

Would it be possible to install a car alarm small horn instead of the buzzer, will hear it much louder when with up wind along engine noise.

Happy Boating
 

Derrick Fronckowiak

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If I put a car alarm in place of the buzzer I might crap my pants and have a coronary if it goes off. Thanks again for the advice.
 

Derrick Fronckowiak

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Pulling the thermostat (and that little plug above it if the gods allow it) this weekend (weather permitting). Will take pics and share.
 
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