Whaler Central - Boston Whaler Boat Information and Photos

Posted by Beso21 on 01/27/13 - 6:21 PM

Have 1985 Johnson 90, but the VRO has been disconected.Now I mix my fuel. I have the overheating alarm go of aboutf 3700 rpm and I will shut down check every thing out, no obstructions, temp of heads are only warm. Impeller and water pump changed app. year ago. I will start up no alarm and fish the rest of day and never hear alarm again. My mechanic tells me that it is a bad alarm for he has checked every possible cause out. Any body ever had similar issues.

Edited by Joe Kriz on 01/28/13 - 5:19 PM

Posted by Joe Kriz on 01/27/13 - 6:25 PM

You don't mention the brand of your motor.
OMC?

See this article and test a few things yourself.
http://www.whalercentral.com/articles...ticle_id=9

If you have never replaced the horn, then I would replace it with the newest version that has the test beep when you turn the key on per the article above.

Edited by Joe Kriz on 01/27/13 - 6:26 PM

Posted by contender250 on 01/28/13 - 5:04 PM

Check and rebuilt the carbs, If one is not operating properly will cause the one cylinder to get hot and sound the alarm. Also check the termostatos. Just because the impeller was changed a tear ago does not mean its still good, also only replace the water pump (purchase the kit from OMC) with factory equipment

Posted by Derwd24 on 01/28/13 - 5:18 PM

Also keep in mind that on some engines there is a vacuum sensor in the fuel system that will sound the solid alarm when it senses a restriction in the fuel line. This is usually caused by a kinked line or bleed screw that's not fully open. The alarm mainly gets triggered in the higher RPM range when the demand for fuel is greater and the vac sensor is more easily tripped due to restriction....

Posted by seahorse on 01/28/13 - 9:11 PM

What does the alarm sound like?

a steady tone?

a repetative on and off sound about 1/2 second apart?

a beep about every 30 seconds?

does the alarm stay on even when you pull the throttle back?

Posted by seahorse on 01/29/13 - 10:14 PM

Beso21 wrote:
Alarm is steady and stays on after throttle is pulled back

If it goes away after the motor cools down, it sure sounds like an overheat condition or it could be a bad temp switch or shorted wire.

Those motors have a history of thermostat and pressure relief valve problems due to the design and location of the thermostats housing. Salt or mud deposits can build up in the cylinderhead passageways near the temp switch locations. Those blockages or restrictions often cause localized hot spots that can trigger the over-temp switch.

If you find brass thermostats in your motor, they are either old versions or off-brand types. Factory thermostats for that motor have been stainless steel for many years.