temperature alarm

[fisherman363]

I have a 1998 yamaha 25 hp two stroke outboard model # 25ELRW. I don't believe it has a high temp alarm and I'd like to install one. Is there something like this available available?.

[99yam40]

all of the outboard I have seen have an overheat switch mounted close to the top of the head that sounds an alarm and limits RPM so that you can react and turn it off before destroying the motor

[fisherman363]

This is a 1998 motor - I don't believe it came with an overhear switch?

[99yam40]

find an owners manual for it on the Yamaha web site or somewhere on the web and read up.
motors a lot older than that had them

[fairdeal]

I see a "thermo switch" in the parts list
but I don't know what the red notation "O/I" means

Perhaps Boscoe can explain

[fisherman363]

therm.jpg It looks like the well in this picture is where the thermo switch would go. doesn't look like there ever was one there. Switch new is close to $100 when you figure in the shipping. The buzzer is not available- I picked up a used switch ( same part number) on E-bay for $15 and will hook up a generic buzzer. Thanks for the help. Bill

[99yam40]

the R means this is a remote con*****ed motor, what con*****er do you have?
the buzzer is usually inside that

seems like I remember something about the radioshack buzzers did not always work well in these things.
not sure why

[DennisG01]

I would think your idea/plan should be just fine. After all, a temp sensor is really just a simple switch, feeding +12V to the buzzer. Just put the buzzer in a protected area by the helm - their sound is pretty piercing so you can even put it behind something. Or, if you don't like the buzzer, use a red LED warning light, instead... or both.

[boscoe99]

Look at the main engine wire harness please. Not a lot to look at. Do you see a pink and a black wire that are unconnected? In the vicinity of where the thermoswitch wires would connect?

Does the front of the motor have a warning light?|

Does your control box have a warning horn in it?

[boscoe99]

I would think your idea/plan should be just fine. After all, a temp sensor is really just a simple switch, feeding +12V to the buzzer. Just put the buzzer in a protected area by the helm - their sound is pretty piercing so you can even put it behind something. Or, if you don't like the buzzer, use a red LED warning light, instead... or both.

Close but no cigar. The thermoswitch closing feeds the ground to the buzzer. The buzzer gets +12 volts from the key switch.

[DennisG01]

Close but no cigar. The thermoswitch closing feeds the ground to the buzzer. The buzzer gets +12 volts from the key switch.

You're right - got me on that one - I responded without thinking much on that part... But that's OK, I don't smoke I guess my main point was just that it's a simple switch... closed/open... so hooking this up should be about as basic as basic can be.

[fisherman363]

Thanks for this information- It seems from what I'm reading in the manual the remote con*****er may or may not contain a buzzer alarm. I'll check for the unconnected pink and black wire - there is no warning light on the motor or anywhere else. If I use a generic buzzer I assume I could just run a hot feed to the buzzer and run the other buzzer lead thru the thermoswitch to ground. When the the thermoswitch closes due to overheating that would complete the circuit and the buzzer would sound. Dennis and Boscoe, does this look like a working alarm to you. Thanks again Bill

[fisherman363]

Looking at the wiring diagram if there are pink and black unconnected wires the buzzer should sound if I ground the pink wire. That's assuming there is a buzzer in the remote con*****er?

[99yam40]

Looking at the wiring diagram if there are pink and black unconnected wires the buzzer should sound if I ground the pink wire. That's assuming there is a buzzer in the remote con*****er?

that is correct, with the key in the on position

[DennisG01]

Yes, you are correct. A simple switch - like turning a lightswitch on/off. Just be sure to use a "switched" +12V supply as there's no need to have this powered all the time. Although, ideally, it's on a circuit that is switched on when the key is turned to the "on" position, I suppose fo ryour purposes, it could really be any circuit that is con*****ed by the battery circuit... but I don't know if there could be a case where after running the engine for a while, and then shutting it down (but still with the battery switch on... drift fishing, for example), there would be enough heat soak to trip the swtich. Just thinking outloud on the last part.