Adding a temperature alarm

With all the horror stories about motors overheating due to whatever reason, I was wondering if someone sells an after market temperature alarm for motors that never came with one. Maybe something that also tells the temperature so I can set the alarm to go off if the temperature goes above normal.

DLH

Re: Adding a temperature alarm

Yes, there are aftermarket temperature alarms and temperature senders/gauges. Either type will use a head bolt and clamp to secure the sensor in contact with the head. Some can be screwed into a drilled and tapped hole in a suitable boss on either the head or block.

The only small problem with the clamp-on type is that they are a little slower to respond because the simply are touching the head.

I do not remember the brand names but I am sure that if you look in your local dealer, ********, West Marine, and here at Iboats, you should find what you need.

Re: Adding a temperature alarm

Which HP engine do you plan to place one, does it have a heat sensor which turns rpm down or shuts engine off ?

Happy Boating

Re: Adding a temperature alarm

Thanks,

Did some searching and found a lot of options but so far none with a settable high temp alarm. Will take a good look at my motor to see if there is a boss that I can drill and tap.

Here's a question. About those temperature gauges that mount under a head bolt. Is that a good idea to remove one head bolt and then re-torque it. Seems like that's a good way to warp the head.

DLH

Re: Adding a temperature alarm

Sea Rider said:

Which HP engine do you plan to place one, does it have a heat sensor which turns rpm down or shuts engine off ?

Happy Boating

Click to expand...

It's for my 1980 35 hp pull start Evinrude. Not sure if a temperature gauge was an option. I have a boat battery, solar charged, to run my electronics, that I could use to run the gauge.

DLH

Re: Adding a temperature alarm

Old standard technology, the issue with gauges is that unless you find a proper spot to install probe to read fast overheats and trigger the alarm are near useless. Could work fine If yo have a slow overheat due to semi clogged water passages, 2 stroke oil issues mix, oil pump failure, whatever, and that's at slow speed.

Worst scenarion, if you were runing at 3/4 to wot and a plastic sheet, paper even a banana peel blocks your lower tail water intalkes, temp will rise so high fast that sensor will not have time to trigger the alarm and protect engine. How about installing a thermo fuse, like the ones that protects appliances that produces heat as in hair dryers, house irons, the small ones that blow open when a certain temp has been reached and shutts down whatever it was attached to. Are available in different temp ranges, a matter to know which temp will suit best your engine.

It's like runing your car on a highway at speed and blowing you radiator, as there's no inmediate indication of this problem, while gauge detects this as an overheat, probably you're are done with your engine. Personally have fried 3 portables due to water intake blockages at speed.

Happy Boating

Re: Adding a temperature alarm

When I bought my motor in 1980 the store owner told me to be careful of the water intake because it was noted to get blocked by weeds. It's never happened but that doesn't mean it won't. I'm looking for an alarm that I can set the trigger point 25 degrees,or what ever, above normal temperature. I would run the motor under idea conditions then set the high point. The one thing that might be a problem is the motor might run at a significantly different temperature at trolling speeds than wide open.

DLH

Re: Adding a temperature alarm

i have pondered using a normally open snap disk thermometer/switch, attached to the head. they are only a couple of bucks and come in many heat ranges. my plan is to use the snap disk and a cheap buzzer ( radio shack)to alarm off head temp. i realize the plan has its flaws, but for the 1950's motors i use, i figure i can use an ir gun to see what temp the head usually runs at at wot in warm water , and get a disk that trips at say 10 degrees above that.

Re: Adding a temperature alarm

nwcove said:

i have pondered using a normally open snap disk thermometer/switch, attached to the head. they are only a couple of bucks and come in many heat ranges. my plan is to use the snap disk and a cheap buzzer ( radio shack)to alarm off head temp. i realize the plan has its flaws, but for the 1950's motors i use, i figure i can use an ir gun to see what temp the head usually runs at at wot in warm water , and get a disk that trips at say 10 degrees above that.

Click to expand...

Going to have to Google "normally open snap disk thermometer/switch".

I found a couple possibilities. I prefer the LCD one with the 85 dB buzzer but I can't find the price.

TM2 Engine Watchdog - Digital Temp Gauge with Alarm - Full Wave Marine

CruzPro Digital Water Temp Gage With Alarm

DLH

Re: Adding a temperature alarm

looks like the kit is $150 aussie dollars?. nice that it has an lcd readout. for less than $20, you should be able to do the same thing, but no digital readout. ( and for another few bucks you could wire up a test button to ensure the warning buzzer is working!) jmo