Whaler Central - Boston Whaler Boat Information and Photos

Posted by kevin nolan on 07/21/09 - 6:27 PM

i just cheeked my temp alarm om my 17 montauk it has a 1990 88 special evenrude the alarm was bad so i changed it and the new one cheeked out ok . now i am wondering if i should cheek the temp switch but i see i have to take apart the head to get to them , i am thinking maybe not. so is there a way to test the switches with them still in the heads. and do they really ever go bad. thanks for any suggestion.

Edited by kevin nolan on 07/23/09 - 3:34 PM

Posted by Guts on 07/23/09 - 4:09 PM

I would run it hard for a short time and feel the water temp where it comes out, if you can hold your hand after running hard it's ok. I don' know if yours is a temp. sending unit in a water jacket or just a sensor pushed tight to the head.

Posted by Joe Kriz on 07/23/09 - 4:11 PM

Kevin,

First and Foremost, this is a Boston Whaler site, not an outboard motor site.
Although many people can be helped with their engine problems, apparently the people that read your post do not have the answer.

If no one can answer your question, I think it would be a good idea for you to buy a manual for your engine.

Posted by theo on 07/24/09 - 8:00 AM

Kevin, I saw your thread and couldn't offer much advice so I didn't reply. If you want me to shoot from the hip here you go: :)

The Temp switch, on some outboards at least, is normally open. If it gets too hot it closes, which connects the circuit to ground and sets off the buzzer. The buzzer has power to it all the time (with the key on), just waiting for one of the sensors to close.

If you could heat just the Temp sensor with the key on you should be able to get it to close. I just can't recommend a good way of heating the switch without heating the head unless you remove the switch. Then you could put an ohm meter on it and drop it in hot water.

You can't run the motor without water. That would work to heat the block, and you could monitor it with heat sensitive crayons or similar and shut it down in time, but you'd burn up your impeller in no time.

You might be able to get the sensor hot enough with a heat gun, but I'd be careful because you'd be applying uneven heat to the head.

That's about all I can come up with for now. I agree with Joe about having a service manual. Worth the investment. Good luck. WC is still a good place. You'll see.

Posted by MW on 07/24/09 - 9:10 AM

You'd need a controlled experiment with a pyrex glass, burner, water, and Thermometer, maybe you could get the sensor in that, I ""THINK"" with an ohm meter attached. It's NOT that we've ignored your question, it's just that you've "Stumped the Band" (we don't know that one).

Posted by bruser on 07/24/09 - 9:31 AM

I would hate to send you to another web site, however if you go to iboat.com you can get an exploded view of your particular engine. It will also give you part numbers.
From there search the "Johnson outboard" page for overheating or temprature gage and I am sure after a few moments of reading you can get the information you are looking for.
Give it a try and let me know, I have a johnson repair manual that covers most outboards but it is the worst repair information source ever created( not non-technician friendly)

Posted by Derwd24 on 07/24/09 - 11:24 AM

Here's a link to a pic of the temp switch in the head of your particular engine (original p/n was superceded to this one). As the guys above have said, removal is probably the easiest way to test it, and it looks like the cyl head covers would have to come off for that to happen as there appears to be one on each side according to the BRP parts site. No easy way unfortunately.

http://www.marineengine.com/parts/par...amp;Model=