Ranger 391XT project boat electrical question

danrnsmyth

New member
I have an older Ranger I have been working on as a project boat and it has a 1996 Mercury EFI Motor. When I turn the key what I hear is a click..clickety-click in a short span but no beeps...just clicks. My assumption is that I have a mechanically defective warning horn that is getting voltage but lost its beep...has anyone else ran into that issue?? The warning horn is zip tied onto a big cluster of wires right behind the ignition switch and looks kinda like the old signal light flasher relay
 

FishingwithRusty

Active member
i had an issue like that, turned out to be the ignition switch. will the motor fire and run normally?
 

silvertalon

Active member
You can test your horn by jumping your cylinder head temp sensor (tan or tan blue), to ground with the key on. The horn should sound. If you still hear the clicking sound, that would indicate a faulty horn. Also, ground a volt meter and probe the purple ign wire at the horn. If you don't get 12V plus (key on), it could be the key switch. Don't forget the ground wire to the horn. Power a test light or volt meter and probe the black wire. A dim light or low volts, would indicate a poor ground. It's imparitive you fix this in the event that an overheat or oil injection issue should occur. Also, the reason for the beep tone (s), when you turn the key on, is to indicate that all the wiring and the warning module are functioning properly.
 

danrnsmyth

New member
Thanks, that will be of great help. I am not going to run it until that is diagnosed. I have cranked it on muffs with some premix fuel so it smokes a lot and ran it a few minutes and tried to monitor the engine temps using a little infared temp sensor gun, which I assume is somewhat inexact so it was only ran less than 30 seconds...
 

FishingwithRusty

Active member
silvertalon - 7/15/2019 2:02 PM

You can test your horn by jumping your cylinder head temp sensor (tan or tan blue), to ground with the key on. The horn should sound. If you still hear the clicking sound, that would indicate a faulty horn. Also, ground a volt meter and probe the purple ign wire at the horn. If you don't get 12V plus (key on), it could be the key switch. Don't forget the ground wire to the horn. Power a test light or volt meter and probe the black wire. A dim light or low volts, would indicate a poor ground. It's imparitive you fix this in the event that an overheat or oil injection issue should occur. Also, the reason for the beep tone (s), when you turn the key on, is to indicate that all the wiring and the warning module are functioning properly.



thats what im talking about!!!!! trouble shoot, isolate, diagnose rather than just replacing parts
 

silvertalon

Active member
danrnsmyth - 7/15/2019 3:11 PM

Thanks, that will be of great help. I am not going to run it until that is diagnosed. I have cranked it on muffs with some premix fuel so it smokes a lot and ran it a few minutes and tried to monitor the engine temps using a little infared temp sensor gun, which I assume is somewhat inexact so it was only ran less than 30 seconds...

Good deal on the temp tester. almost all Merc 2 strokes run a 143 thermostat. It should take 3-5 mins to get it up to temp. The tell tale pee stream will not pee until the stats opens. If you detect temps over say- 155, you may need a water pump impeller. If it ever hits 180, the horn will sound. Engines with weak impellers that run temps from 155-175 for several years without the horn going off will surely contribute to premature wear of the cylinder walls and ring sticking.
 

danrnsmyth

New member
I have 12.4 volts at the horn by probing the purple wire and grounding at the little termination board under the console with the key on. The other side of the horn has a tan/blue wire not black which confused me . I assume it has to be a ground but it is a tan/blue pin stripe wire like the one back on the motor and it is about six inches long before it splices into a brown wire which is a gauge larger wire. The splice is covered in a velco like tape. On the motor I grounded to the starter ground and slid the probe down the (formerly) waterproof butt connector and heard the horn clicking and there are three tan wires one being tan/blue that come out of a hole below the number 2 cylinder. Stills clicks. I then found a terminal with the two tan wires piggy backed right behind the starter solenoid and grounded the tester and that produced the clicks as well so I assume I have a mechanically defective horn that needs to be replaced. Thanks for the help,,,I have replaced the water pump, and fuel filter and probe on the bottom of the filter..drained the old fuel and dumped it in the old chevy hunting truck
 

danrnsmyth

New member
Horn fixed, thanks Glenn. I ended up looking at the specs on the old horn and duplicating those with a horn from radio shack,,,beeps are back
 
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