Another Warning Horn question

[salukian]

Hi everyone;

Just did an exhaustive search and can't find the answer to my question, so I thought I'd post it up and see what I get back...

I have an '05 Mercury 50hp outboard model # 10-50412DD ser# 1B154920.
It get's maintained and winterized every year by the local marina service.

I put it in the water this year and immediately when I start the motor, the warning horn sounds continuously. I have good water flow out of the pee hole. Oil gauge is full, and engine runs like it's brand new

I guess the question is, what triggers the horn if the engine is obviously cold?

 

[Don S]

Re: Another Warning Horn question

There is a temperature switch located just to the left of #2 cylinder. Disconnect the tan/blu wire and see if your alarm goes off.

 

[j_martin]

Re: Another Warning Horn question

There is a temperature switch located just to the left of #2 cylinder. Disconnect the tan/blu wire and see if your alarm goes off.

That tests the sender. The horn line could be shorted anywhere between the temp sensor, or the oil alert and the control box, or even inside the controls. Grounding it sounds the horn.

Bout all you can do is disconnect things until you find the trouble.

hope it helps
John

 

[salukian]

Re: Another Warning Horn question

It's a short somewhere. I pulled the tan wire off the temp sensor on # 2 and it stays on. Then pulled the purple off the oil sensor, turned the key to the run position, horn still on.
So, called my mechanic, on a holiday, he came out. Good guy. Did the same thing. Called it a short somewhere and said he would find it later this week. Disconnected the horn and called it good.

Thanks for the help. I'll post up what we find later in the week.

 

[marty53]

Re: Another Warning Horn question

Any resolution on this?

 

[salukian]

Re: Another Warning Horn question

Fellas:

Thanks guys. It was a faulty (internal short) temperature sensor/switch. (Made in China) Problem was, no matter what we tried, the stupid thing sounded off. The only thing that would stop it was to disconnect the horn. So, we ordered a new sensor and replaced Friday. Problem solved.

For a couple days, I was just worried sick I was going to overheat, but the horn sounded, although faint, as soon as the motor was started. Like I posted above, there was good water circulation and oil level.

This Merc, although it's an '05, is well maintained and I'm just a nutbag about taking care of my boats, so it really came as a surprise. I just guess it's one of those wierd things....

One good note, I've spent a lot more time here reading.

 

[longshanks]

Re: Another Warning Horn question

Hi Salukian. Fellow nut-bag and boat maintainer with a Merc 50 four stroke here. Not sure what is going on with mine, but on average of 1x per outing, I get a solid-tone warning, and the motor goes into guardian mode. I had it into the shop last week, and was charged $100 for them to download the computer writeout, and tell me that there is no overheating of the motor happening. There seems to be no consistent reason why this happens, yesterday it sounded and shut down, as I was decelerating, coming into shore. Any suggestions?

Otherwise, the motor runs like a champ, and I'm impressed with it.