1998 mercury 40 buzzer alarm

[gahunter706]

I took my boat out last night and about 5 minutes into the ride the buzzer alarm started going off. The motor is a 1998 Mercury 40hp. The alarm has went off before, but most of the time it would be in below freezing temps and it would stop once it warmed up. It ran fine, had a full tank of oil, and water flow was good. I figured it would go off after a while, but after 12+ hours of sitting in my yard not running, the alarm still goes off when I turn the key on with the engine off. Any ideas what would cause this? Thanks.

 

[carholme]

Re: 1998 mercury 40 buzzer alarm

What kind of beep, solid or intermittent?

Have you tried the testing in the service manual?

Problem: Warning Horn Stays On When Ignition Key is Turned to “ON” Position (Engine Cold).

If warning horn sounds a continuous “beep”, the engine
overheat sensor may be faulty. Disconnect tan/blue overheat
sensor lead at bullet connection. Turn ignition key to
“ON” position. If horn stops sounding, the engine overheat
sensor is faulty.

Problem: Warning Horn Sounds (Continuous Beep) When Engine is Running and Oil Tank is Full.

Disconnect both low oil sensor leads (blue) at bullet connections.
Connect an ohmmeter between sensor leads.
There should be no continuity through sensor. If continuity
exists, sensor is faulty.

Gerry

 

[gahunter706]

Re: 1998 mercury 40 buzzer alarm

What kind of beep, solid or intermittent?

Have you tried the testing in the service manual?

Problem: Warning Horn Stays On When Ignition Key is Turned to “ON” Position (Engine Cold).

If warning horn sounds a continuous “beep”, the engine
overheat sensor may be faulty. Disconnect tan/blue overheat
sensor lead at bullet connection. Turn ignition key to
“ON” position. If horn stops sounding, the engine overheat
sensor is faulty.

Problem: Warning Horn Sounds (Continuous Beep) When Engine is Running and Oil Tank is Full.

Disconnect both low oil sensor leads (blue) at bullet connections.
Connect an ohmmeter between sensor leads.
There should be no continuity through sensor. If continuity
exists, sensor is faulty.

Gerry

The beep is continuous, and no, I didn't think to check the service manual. When it says to disconnect at the bullet connection, is that the connections inside the control box?

Edit: Nevermind, I looked under the hood of the motor and saw the tan/blue and blue wires. I disconnected the tan/blue and it is still buzzing when I turn the key on. Once I find my ohm meter I will check the blue wire for continuity.

 

[kmbvhlowe]

Re: 1998 mercury 40 buzzer alarm

Gerry I just bought my 40 how Mercury and apparently the alarm had been disconnected. I saw in another thread that you had a wiring diagram. Is there some way you can forward it to me?

 

[carholme]

Re: 1998 mercury 40 buzzer alarm

Do you have the s/n of your engine?

Gerry

 

[kmbvhlowe]

Re: 1998 mercury 40 buzzer alarm

Will get it to you tomorrow. Thank you.

 

[kmbvhlowe]

Re: 1998 mercury 40 buzzer alarm

Sorry took me a couple of days. Been working. 0t007004

 

[carholme]

Re: 1998 mercury 40 buzzer alarm

Your s/n comes up as:

MERCURY - ( 40 H.P. (2000 ))
Serial No: 0T007004 Model No: 1043412WD

Parts and Service Bulletin list for s/n 0T007004

Search Results - Crowley Marine

The service manual you require is P/N 90-852572. Responded to your PM, still need an email address.

Gerry