Strange Johnson Alarm

[mlewis]

OK, I've tried and tried with no success to answer my own question, but am at a loss. I'm hoping someone can help me.

I have a 91 Johnson 150 VRO on a 20' Crestliner CC. I have an annoying alarm: When I turn the key on, I get a strong BEEEEEP, which I understand is normal ... but then the alarm starts chirping and remains chirping. I have disconnected all VRO pump wiring, removed the tank and it's related wires, plugged the oil inlet, and am premixing (VRO was working fine - I prefer premixing and engine seems to run better/stronger and idles better, although it will not hold an idle for very long before stalling - but that's a separate issue). I have tested the overheat alarms and, when grounded, my alarm sound goes from chirping to a strong BEEP, so I'm satistied that they are working properly. I have good compression, tight bulb when pumped up, no obvious fuel leaks. Fuel lines and bulbs are new, new spin-on filter, new inline filter, fresh fuel...

So why is my alarm continually chirping?

 

[woody66912]

Re: Strange Johnson Alarm

try putting a volt meeter between the purple and tan wire where the horn hooks ups there should be no voltage their with engine running. if no voltage is found then your horn has failed.if you have trace voltage .you will have to trace the tan wire and find the source where this wire is going to ground.

 

[mlewis]

Re: Strange Johnson Alarm

Thanks - I'll test the voltage.

I'm not sure I understand, though; you say that I should find no voltage there, but that if I find no voltage, the horn is bad ... I'm assuming that there should be no voltage, regardless. The horn seems to be working as it should.

If I do find trace voltage, which wire should I trace for ground fault? I'm assuming the tank wire, since that's the one that grounds to complete the circuit when sensors allow.

I also don't understand the relevance of the engine running. Please advise further. This constant chirping occurs with the engine off - just the key on.

Thanks again for the help, and please forgive my newbie questions.

 

[woody66912]

Re: Strange Johnson Alarm

the purple wire is key on power. i [assume] you have a three wire horn.a purple tan and black. when is self tests on key up. inside the horn voltage goes to ground moteraly for the report then opends the black wire[ ground]to shut off horn.if this cuicit fails to open then the horn will keep sounding or chirpping.sorry i should of put this in the first reply.

 

[mlewis]

Re: Strange Johnson Alarm

That makes perfect sense. Thanks for the clarification!

 

[ottertail]

Re: Strange Johnson Alarm

Check the voltage regulator if all else is good. I have had failed regualtors set the horn off the way your is thru the purple lead on the regulator.

 

[mlewis]

Re: Strange Johnson Alarm

Thank you for that suggestion, too. I'll definately check the voltage regulator. I have a Seloc manual - hopefully it'll be useful this time (haven't found it terribly useful so far).

 

[mlewis]

Re: Strange Johnson Alarm

Woody, let me ask you this. If I were to disconnect the black wire from the horn, I would theoretically lose the short "Key On Test," but the alarm would still sound in an overheat or fuel restriction situation, right? In short, I'd no longer get a test sound from the horn - I'd have to check it myself on occasion.

Is there a test for this horn to prove conclusively whether it is good or bad?

Speaking of the fuel restriction alarm, where on earth is the "sender" for this? I've found two overheat sensors (one on each head) but cannot locate another tan wire, except for the ones I disconnected when I removed the VRO tank and disconnected the pump wiring harness.

 

[woody66912]

Re: Strange Johnson Alarm

no i have never found a good test for the horn.i just keep a good one to swap out.and i think your right on the ground wire removal only one way to find out right.i just looked at the parts break down of the intake manifold i don't see the vacuum switch.but i also don't have your model#.?

 

[mlewis]

Re: Strange Johnson Alarm

I think I wasted my money on this Seloc manual. So far, it hasn't done me much good at all.

I now need it to help me test the voltage regulator, but I can't find even a mention of a voltage regulator, much less how to test it ...

FYI - My engine is a J150TLASB.

 

[woody66912]

Re: Strange Johnson Alarm

i rechecked for vacuum switch nope not there. but i did notice your model # shows it's a 1990.besides the normal volt output test i will check the shop manuel tomorrow for any special tests and get back to ya.

 

[mlewis]

Re: Strange Johnson Alarm

Very cool of you to check on this for me. I sincerely appreciate it!

 

[mlewis]

Re: Strange Johnson Alarm

What is the danger -- what are the cons -- of running with my voltage regulator not working?

 

[mlewis]

Re: Strange Johnson Alarm

OK, I finally found the problem. One of the overheat sensors (starboard bank) was apparently going bad; when disconnected, I get no chirpping. When connected, it chirps continuously. When grounded altogether, it alarms continuously.