Over heating horn

anglerlaz

anglerlaz

Cadet
Joined
Jun 20, 2010
Messages
8
I keep getting a overheating buzzer on my 1991 175 Evinrude. Ive changed the Diverter tubes gaskets, Thermostats, Both sensors, Water pump kit. Now when i go out it starts to sound before i get out the last bouy.has any one experianced this, any help will be apreciated,Thanks.
 
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d.boat

Chief Petty Officer
Joined
Sep 19, 2008
Messages
520
Re: Over heating horn

Are you sure it's overheating? Does it go into SLOW mode? How's the water pressure (if you have a gauge) or telltale? Have you tried measuring the temp of the engine with a heat gun?

What is the exact horn pattern - constant or intermittent? Constant horn can mean overheat or fuel restriction. The main difference is that overheat will sound the horn and go into SLOW mode. Fuel restriction will generally only happen when you're going fairly high RPMs and then will disappear when you back off.
 
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bob johnson

Rear Admiral
Joined
Feb 25, 2009
Messages
4,304
Re: Over heating horn

anglerlaz said:
I keep getting a overheating buzzer on my 1991 175 Evinrude. Ive changed the Diverter tubes gaskets, Thermostats, Both sensors, Water pump kit. Now when i go out it starts to sound before i get out the last bouy.has any one experianced this, any help will be apreciated,Thanks.
Click to expand...

does the horn shut off on its own eventually?

or do you just deal with it???

or do you turn around and go back in and shut it down?


I ask because I think the horn system can have a flaw,...mine does

the constant horn comes on exactly 2 minutes after I turn the motor on...EVERY SINGLE time..and it sounds for exactly 10 seconds...then goes off, ....till i shut the motor down and when i start it back up the whole things happens again at the same interval....but the motor is running good...


I am thinking of just putting some sound proffing on the horn to knock the volume down some...

I know i go out the harbor and every marina that hears it is think

Ha ha ha, that idiot is about to ruin his motor.....

bob
 
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wilde1j

Vice Admiral
Joined
Apr 15, 2002
Messages
5,964
Re: Over heating horn

d.boat said:
Are you sure it's overheating? Does it go into SLOW mode? How's the water pressure (if you have a gauge) or telltale? Have you tried measuring the temp of the engine with a heat gun?

What is the exact horn pattern - constant or intermittent? Constant horn can mean overheat or fuel restriction. The main difference is that overheat will sound the horn and go into SLOW mode. Fuel restriction will generally only happen when you're going fairly high RPMs and then will disappear when you back off.
Click to expand...

^^^ agree!
 
anglerlaz

anglerlaz

Cadet
Joined
Jun 20, 2010
Messages
8
Re: Over heating horn

yes it does go into slow mode. Then when it cools down i have to turn the key off so it will go full throttle again.
 
anglerlaz

anglerlaz

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Joined
Jun 20, 2010
Messages
8
Re: Over heating horn

Actually it goes on afetr about 10 min of running so i idle back but before i reach the dock it turns itself off. Then i head out agien to try it out and the same thing happens over and over, i also changed the horn alrready. and its not ful because my engine has the vro taken out, and the wires are removed so the only horn i will be able to get is the over heating horn. I mix the oil and gas myself.
 
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wilde1j

Vice Admiral
Joined
Apr 15, 2002
Messages
5,964
Re: Over heating horn

If it's overheating, fix it! If you can't place your fingers on the cylinder heads for a few seconds or more, it's overheating or use an infrared gun ... normal is 140 to 150? F.

DO NOT CONTINUE USING THE BOAT UNTIL IT's FIXED.
 
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d.boat

Chief Petty Officer
Joined
Sep 19, 2008
Messages
520
Re: Over heating horn

anglerlaz said:
yes it does go into slow mode. Then when it cools down i have to turn the key off so it will go full throttle again.
Click to expand...

anglerlaz said:
...and its not ful because my engine has the vro taken out, and the wires are removed so the only horn i will be able to get is the over heating horn. I mix the oil and gas myself.
Click to expand...

Actually, the fuel restriction alarm has nothing to do with whether you removed the VRO and pre-mix the fuel (and disconnected those wires). Fuel restriction is caused by a vacuum switch that is near the fuel pump, but is not actually part of it. Its wiring is not part of the VRO/OMS fuel pump no oil alarm wiring.

Anyway, that really doesn't matter because as you said (above), it def. sounds like an overheat alarm. BUT, you should really determine whether it's an actual overheat or an alarm malfunction. Use the "touch" test as wilde1j said, or get an (inexpensive) infrared heat testing gun and measure it - both sides. With all the stuff you worked on it SHOULD be cooling OK, but you never know. I'd try to figure out what the temp actually is when the alarm sounds. Do it right away when you shut down when the alarm goes off, so you don't really overheat the engine.
 
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boobie

Supreme Mariner
Joined
Nov 5, 2009
Messages
20,826
Re: Over heating horn

I agree with the above. Get a temp gun and actually see if it's overheating or not. One thing to remember about SLOW on this mtr, you have to stop flywheel rotation to get it out of slow mode.IE: shut the mtr off.
 
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emdsapmgr

Supreme Mariner
Joined
Dec 9, 2005
Messages
11,551
Re: Over heating horn

It would be interesting to see what is inside the heads. Have you considered pulling the head covers off? Always possible there is some debris in them, restricting water flow. Those head cover gaskets aren't real expensive and you don't have to pull the heads. A laser temp gun will easily show the cyl head temps and whether one or both heads are overheating. On that model you will get an overheat (SLOW mode) at 203 degrees on either head. SLOW will cancel when the cyl head gets back down to 163 degrees.
 
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cobia1970

Seaman Apprentice
Joined
May 26, 2010
Messages
42
Re: Over heating horn

im in the same sitituation when i go wot the alarm goes off in about 5 min alarm lasts about 20 sec.if i dont go full throttle its fine. i replace the impeller and the thermos, still doing the same thing. i think mine may be fuel when im at wot the motor starts to sputter will go fast for a sec then slow down.
 
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emdsapmgr

Supreme Mariner
Joined
Dec 9, 2005
Messages
11,551
Re: Over heating horn

You may also have a weak fuel pump. Try constantly priming the fuel hose bulb to force extra fuel directly into the carb bowls. See how it runs at that point.
 
anglerlaz

anglerlaz

Cadet
Joined
Jun 20, 2010
Messages
8
Re: Over heating horn

The gas isnt the problem it will take off and plane before the horn goes on. Im going to take out the lower unit and check the water feed tube going up to the engine, maybe its got particals stuck in there fron the bad impeller i changed.
 
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d.boat

Chief Petty Officer
Joined
Sep 19, 2008
Messages
520
Re: Over heating horn

anglerlaz said:
The gas isnt the problem it will take off and plane before the horn goes on. Im going to take out the lower unit and check the water feed tube going up to the engine, maybe its got particals stuck in there fron the bad impeller i changed.
Click to expand...

I still think you should figure out if its really over heating or not. At least feel both sides with your hand, but best to shoot it with an IR temp gun and see what it actually measures.
 
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