Constant beeping alarm on 95' MERCURY Black max.

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ProCraft17

Cadet
Joined
Jul 7, 2011
Messages
15
at idle everything is running fine including waterpump. After about 2 mins on plane constant beeping allarm sounds. I turned it off for 3 mins and when it comes on no alarm. I mix my own oil at the recommended 50:1 ratio .

Any ideas how to trouble shoot this?
Thanks
 
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CharlieB

Vice Admiral
Joined
Apr 10, 2007
Messages
5,617
Re: Constant beeping alarm on 95' MERCURY Black max.

Is it a solid tone or a rapid beeping?

Solid tone is a cooling problem that could be a number of things, leaking head gasket can displace cooling flow and cause a rapid overheat seem to cool fine at low throttle positions.

Check compression on each cyl to see if there is a slightly lower reading on one cyl.

Pre-mixing fuel? Has the oil alarm been removed/disconnected? Most likely you are getting a solid tone heat alarm, not a rapid beeping.
 
P

ProCraft17

Cadet
Joined
Jul 7, 2011
Messages
15
Re: Constant beeping alarm on 95' MERCURY Black max.

yes it is a constant sound.

how do i go about checking the compression?
 
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ProCraft17

Cadet
Joined
Jul 7, 2011
Messages
15
Re: Constant beeping alarm on 95' MERCURY Black max.

What sensors/ plugs do i need to locate and clean also.

Im trying to take it out monday and would love to have it running.
any help?
 
J

JohnQ-FWB

Seaman
Joined
Oct 3, 2007
Messages
51
Re: Constant beeping alarm on 95' MERCURY Black max.

Same thing on my 1995 Black Max. Started & Ran fine at idle, no problem slow motoring away from the dock. Got it up on plane for about a quarter mile & it start the solid screaming. Shut it down, raise the motor and checked for kelp (happened before), no kelp. Put motor down, restarted fine, slow motored fine, up on plane after a short time, solid alarm again. No Nooky (Chinook) this weekend & expensive shop on Monday.
 
j_martin

j_martin

Admiral
Joined
Sep 22, 2006
Messages
7,474
Re: Constant beeping alarm on 95' MERCURY Black max.

Quite simply, it's overheating, or the overtemp switch is defective. You have to determine which and fix it.
 
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JohnQ-FWB

Seaman
Joined
Oct 3, 2007
Messages
51
Re: Constant beeping alarm on 95' MERCURY Black max.

JohnQ-FWB said:
Same thing on my 1995 Black Max. Started & Ran fine at idle, no problem slow motoring away from the dock. Got it up on plane for about a quarter mile & it start the solid screaming. Shut it down, raise the motor and checked for kelp (happened before), no kelp. Put motor down, restarted fine, slow motored fine, up on plane after a short time, solid alarm again. No Nooky (Chinook) this weekend & expensive shop on Monday.
Click to expand...

The impeller was getting old and spun on the hub. Low engine rpm it would pump, but as rpm rose, the impeller would not pump worth a darn. Picking up fixed boat this morning.
 
J

JanetM

Recruit
Joined
Jul 21, 2011
Messages
2
Re: Constant beeping alarm on 95' MERCURY Black max.

Had a similar problem with a '97 Mercury Bigfoot. After several things that didn't work we flushed the cooling system (water intake) and it did the trick......good luck!
 
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