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tachometer problem

M

Mugsbuttons

New member
Hello-Brand new to the forum and may not be in the right section. I took off a 1991 Johnson 115 hp v-4 2 stroke and put on a 112 hp SPL v-4 2 stroke Evinrude. All is working as it should except the tachometer. The tach needle will rest at about 3000 rpm when the engine is off. When the ignition is turned to the "run" position, the needle will zero as it should. When the engine is started, the needle remains at zero. No movement at all. When I remove the "gray pulse" wire and hook up an ohmmeter and set it to AC it reads 6 volts, which it should. As you rev the engine the ohmmeter needle falls which seems strange. I am suspecting a bad gauge. The tach needle does rise and fall on the 12 volt side but no reading on the pulse side yet I have voltage through the gray wire. What you guys think?
 
papyson said:
what does the voltmeter on the instrument panel read?
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No voltmeter on dash. I have been trying to test the regulator ( this one is water cooler) but don't really understand the lingo-like &#40 does not mean anything to me. What I did do is remove all the regulator wires from the starboard engine terminal block. I put the black wire from my ohmmeter to the case of the regulator and the red lead to the yellow/gray, yellow, gray, red, purple individually. The tach or gray wire made the needle go up slightly as well as the purple. When I reversed the leads the gray wire did the same and the purple wire showed no reading. I did notice a jumper from the yellow to the gray which was not present on the original 1991 Johnson 115. The 115 only had one jumper that involved the red wires. The 112 has two jumpers-one for all the red wires, and another from the yellow to the gray-which does not seem right to me. Starting to suspect the regulator.
I tested the regulator on the 115 and found all results to be the same as above except the purple wire made the ohmmeter needle move up significantly. When the leads were reversed the needle did not move. Thanks for getting back to me! If I can beat this last gremlin, I'm done!
 
the regulator may very well be bad...the jumper from the yellow to the grey is where someone changed the tach drive from the regulator output to the stator output.....hook all the wires back up and see what you read in dc volts between ground and the red regulator output wires...also(with the motor running in both cases) see what you get in ac volts between the two yellow wires coming from the stator..please get back to us on this...
 
papyson said:
the regulator may very well be bad...the jumper from the yellow to the grey is where someone changed the tach drive from the regulator output to the stator output.....hook all the wires back up and see what you read in dc volts between ground and the red regulator output wires...also(with the motor running in both cases) see what you get in ac volts between the two yellow wires coming from the stator..please get back to us on this...
Click to expand...
Will do this on Monday! I think I'll rest on this awhile-I usually figure this stuff out when I walk away awhile-thanks for getting back to me-will report the results as you requested!:)
 
Papyson, it was the regulator! If you want all the nitty gritty results just say the word. I typed them all out and was shut off-no permission-even though I logged in. Oh well.
 
dont need the nitty gritty....someone knew it was bad when they moved the wire to make the tach work...glad its fixed...
 
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