Alarm Sounds steady beep

[Trex3]

Hi, I have a 2002 115hp optimax outboard jet. I took it out the other day it idled with no alarm when I tried to power it up a high pitched continuous tone went on, and it would not go. what could be the problem?

 

[achris]

Re: Alarm Sounds steady beep

Constant tone from the alarm is usually an overheat alarm...

 

[Texasmark]

Re: Alarm Sounds steady beep

Look on the rear of the engine block for the OT sensor.....has a tan wire coming from it and it is embedded into the blocks water jacket, held in place with a clamp and one screw. I have the 3 cyl and it is to the left of the sparkplugs and head water jacket about mid way down the block.

Remove it (let it dangle in space) or just disconnect the tan lead to it and try again. If horn is silent, get a new one. If horn is still on, you have a short somewhere between the horn (low voltage side, - terminal) and ground. If the horn is in the control, like on the 2000 the short could be chafing inside the control.

Mark

 

[Trex3]

Re: Alarm Sounds steady beep

I will check my wires for my alarm. Also when the alarm was going on I had very little motor power ,luckily I had a kicker to get me back to the ramp. Appreciate the help.

 

[ddennis]

Re: Alarm Sounds steady beep

Does it still do it with the engine cold?

 

[Texasmark]

Re: Alarm Sounds steady beep

I didn't offer this earlier as you didn't say that you could make it go off. That's why I discussed the failed OT sensor.

The engine has 2 cooling circuits:

Low speed is thermostat controlled and that is your only water source.

I'm told that at about 2500 rpm, the water pump generates adequate pressure to unseat the popoff valve which is much larger than the stat opening and allows more cooling water through the engine at the higher speeds. It is not temp controlled. The stat may or may not function normally with this open. If so, it's just a parallel path allowing even more cooling water. Additionally, ram water pressure from the lower unit can unseat it also, like you would get when the boat gets up on plane.

So this test would include low speed operation and high speed operation to see if it will be quiet; but it's risky.

Personal example. Bought a boat. Took it out and was just idling around and running low speeds. The solid alarm cam on. After clearing my head and making a few checks for what's going on, I firewalled the throttle. About a minute later the alarm went out. It stayed out till I slowed down again to less than roughly 2000 rpm's where it came on again.

Later trouble shooting proved the problem to be a stuck closed stat and replacement solved the problem. Apparently my popoff valve was functioning normally.

HTH

Mark

 

[Trex3]

Re: Alarm Sounds steady beep

Mark I will check the stat. It sounds like the same thing your boat was doing.
The alarm went off for a little but came right back on. I appreciate the information from everyone. I will let you know what I find. THANKS Rex