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Warning buzzer short?

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Sam110

Regular Contributor
I recently purchased a 1985 Sylvan with an '85 Evinrude 90 hp E90TLCOS which I have discovered (thru preventive testing of the heat and oil level sensors) had previously had the warning buzzer removed. I suspected the reason it had been removed was due to a problem in the circuit somewhere so I called the previous owner to see what he could tell me. He said he never had any problems with the buzzer and didn't know it had been disconnected. He owned the boat since 2001 without any issues with the overheating or VRO. I went to Ebay and found a two wire buzzer cheep and today got it wired to my control box. As I suspected, when the key is in the "on" position I get a constant tone. I disabled the overheat sensors and the low oil sensor one at a time and I still get a constant tone when the key is ON. SO. . apparently I must have a short somewhere in that circuit? Electric diagnostics is not my strong suit. I do have a 'multimeter' and I checked for continuity between the tan wires to the main looms large red connector at the engine and all was good.

The wiring within the control box for the buzzer had two purple wires on a crimped on 'slip' connector and the tan wire had a similar connector. The buzzer I bought only had two wires, the purple and the tan with a blue stripe. No ground wire. It did have a mounting bracket molded into its casing that could possibly act as a ground but I ran the wires outside the control box and do not have the buzzer attached by that bracket. I know this buzzer isn't the identical part # but from what I have read on the topic it will still work.

I received my motor shop manual set and have studied the wiring schematic but . . .? Any ideas what I might want to check next?
 
You have the following warning horn sensors:

Heat sensor - - -1 sensor at each cylinder head.
No oil sensor - - 1 sensing unit in VRO... wires at VRO lead to rubber plug type connector.
Low oil sensor - 1 sensing unit in oil tank - wires connect at powerhead area.

If you disconnected all of them, and the horn continues to sound, the tan wire is shorted at some point.
 
Two heat sensors, a wire lead from the oil tank with two wires, one to ground the other to a knife blade connector looks brown possibly dirty tan and the three wire plug from the VRO pump. I get continuity between the tan wires while they are disconnected.

I disconnected each sensor / wire / plug individually one at a time with no change - a constant tone.

Yes a short somewhere. I'm thinking I'll separate the large red loom connector at the power head and using a long piece of wire testing continuity from there back to the buzzer and see what I get. ???

I might add that my Shop manual says I only have two warning signals one from the heat sensors and a low oil sensor (?) in the oil reservoir.

I believe the VRO has been upgraded from the original as it has the brown fuel connector with the three wire plug.
 
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Sam110 said:
Two heat sensors, a wire lead from the oil tank with two wires, one to ground the other to a knife blade connector looks brown possibly dirty tan and the (1) - three wire plug from the VRO pump. I get continuity between the tan wires while they are disconnected.

I disconnected each sensor / wire / plug individually one at a time with no change - a constant tone.

Yes a short somewhere. I'm thinking I'll separate the large red loom connector at the power head and using a long piece of wire testing continuity from there back to the buzzer and see what I get. ???

(1a) - I believe the VRO has been upgraded from the original as it has the brown fuel connector with the three wire plug

(2) - I might add that my Shop manual says I only have two warning signals one from the heat sensors and a low oil sensor (?) in the oil reservoir.
Click to expand...

1 & 1a - I've forgotten the significance of the "Brown" fuel connector, probably something to do with ethanol, but no matter. The 3 wire plug is a dead giveaway that it has not been upgraded to the four (4) wire system which itself had been upgraded quite a few times. In essence, that three (3) wire VRO is approximately 28 years old and obsolete!

2 - Who published that service manual? If it does indeed state what you're typed out... it is incorrect. The warning horn setup is as follows:

(VRO Horn Warnings)
(J. Reeves)

NOTE: I retired around 1991/92. Possibly some of the later V4 engines and others may also incorporate a fuel vacuum switch that would enable a fuel restriction warning to sound as mentioned below, an unknown factor to myself.

1 - A steady constant beep = Overheating - The V/6 engines, possibly some others, have a fuel restriction warning which is also a steady constant beep.


2 - A beep every 20 or 40 seconds = oil level has dropped to 1/4 tank. (Late model engine = Every 40 seconds)


3 - A beep every other second = VRO failure, air leak in oil line, oil restriction, (anything that would result in a lack of oil being supplied to the engine).

NOTE - If the warning horn is the black plastic (overpriced) three wire type horn, the warning horn should beep once when the ignition key is turned to the ON position. If it does not, it is either faulty or someone has disconnected it (a stupid move!). At any rate, if it does not beep which indicates that the horn is non functional, find out why and do not run the engine until the problem is corrected.
 
The service manual is a Evinrude Johnson Final addition obtained from this site however my comment regarding the VRO fuel nipple being brown leading me to believe it was an updated version came from a reading here:

http://continuouswave.com/whaler/reference/VRO.html

Under heading "A Little History" and under "Distinguishing VRO" it claims the first VRO's of 84 & 85 had no wiring for a warning circuit. This seems to validate why the schematic in the E/J manual I have doesn't show that "No Oil Flow" circuit. My VRO does bare a tag stating "VRO2" and has a three wire circuit from the pump.

E/J manual does state my '85 engine has/had only a two tone warning system, overheat and low oil in the reservoir. V6 of that year had three.

The warning horn (buzzer) was non existent in this boat since before 2001 according to the previous owner who I obtained it from. Parts diagram here at Marine Engine shows the three wire horn as you describe with a ground but the one I have installed does not.
 
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Do all your troubleshooting from th buzzer back to ground. Electricity travels from Neg to positive. Disconnect the engine harness red connector and the test the tan wire to ground (ohms) disconnect components until you get a open circuit at the red connector. Trace the wires from pos to neg you will find the short.
 
Sam.... Your post and explanation of the problem seem so familiar to me... really rings a bell! Did you or a previous owner, if you might be aware of their actions, insert a post here or perhaps some other site's forum some months back?

Yes, the original 1984 VRO had no warning system which resulted in quite a few blown powerheads. That VRO was quickly replaced with a three wire VRO which was obviously an improvement... BUT... it had a flaw which was that it would emit false warnings, hence the four wire VRO which has been upgraded a few times.
 
No Joe, the post is original but I have read others before posting that were eerily similar but didn't quite answer my question of just how would be best to run this problem down.

Initially I was going to flat out eliminate the VRO mixing altogether but after doing some reading here and on other sites I had a change of mind. It worked for the previous owner for 16 yrs and he claimed he had no issues and he denies knowing the horn was missing (either fibbing or never made preventive checks of the warning system period) It was then I decided that if I was going to rely on the system I wanted to be sure the warning system was working as it should. I began with preventive checks as I explained above and discovered the horn was removed / missing. So here I am now trying to determine just why the horn I installed is emitting a constant tone and how best to 'run it down'. I was hoping there might be some "magical" solution the diagnostic crowd on here might know about that would solve it.

Sounds like a way/ place to start Kimcrwbr1. Thanks.
 
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Had one do that once. Go off for no reason. Wouldn't shut up and actually melted into goo before we could get the battery disconnected.
 
NOTE: The following DOES NOT apply here as "Sam" has already replaced the horn with a "Two Wire" horn which would not be affected by this mention. This is just a FYI that others might find helpful.

Should anyone encounter a problem whereas simply turning the key to the ON position causes the overpriced three (3) wire horn to blare steady and constant..................

With the horn sounding, remove the TAN wire from the horn slide on terminal. If the horn continues to sound with this wire removed, the horn is faulty... replace it.

Note that the Tan wire MUST be attached to the slide on terminal closest to the black ground wire. If attached to the other slide on terminal, weird things will occur.
 
Mystery solved. The positive side of the "low oil" warning was still making contact... 'er ah .. wasn't disconnected. That's right the "short" was between my ears! :eek: But as a result I have found that both of the overheat sensors are working and give a tone at the horn when shorted out. Low oil in the tank isn't nearly as worrisome to me as I can easily see the reservoir level. However it does disable the VRO warnings. I will need to pull that oil reservoir I guess to find the problem and hopefully that will bring the system back to 100%. I guess my other option is to eliminate the reservoir entirely and premix my fuel.
 
Sam.... In the above post #15, are you saying that there is a short in both the oil tank (oil "Low" warning) electronics and also the VRO? (warning of "No" oil)
 
Go to master tech marine they have schematics. The low oil is a simple float switch in the reservoir cap the VRO has three wires ground, buzzer and tack signal. The four wire pump I believe also sends a signal to the power pack to throw the engine into limp mode on later models. You just need the two wires for the pressure switch that opens when the engine is running. The buzzer should sound with the key on until the engine is running.
 
No Kim haven't tried doing anything with it at this point. Thanks for the MasterTech tip I'll check them out.

Yes and no Joe, the VRO emits a faint tone (as opposed to a strong loud tone) when the oil reservoir leads are disconnected and the 3 wire VRO plug and its TAN wire at the opposite end of its loom is left connected. I can disconnect the VRO's tan wire while leaving the 3 wire plug connected and the faint tone will stop. I am making an assumption that the fault lies within the disconnected oil reservoir circuit which may be effecting the VRO circuit. Both overheat sensors continue to work if tested by shorting out. It seems the overheat sensors operate independently of the VRO / oil reservoir. I'll have to have a look at the float switch in the oil reservoir circuit before I can be certain the VRO itself is not faulty.

Kim, the three wires from the VRO, tan, black and gray ~ the black and gray are the two your describing that operate a 'pressure switch'? They both are connected to the the terminal bar on the starbord side of the engine. I'll have to look at that schematic in the site you referred me to to better understand.
 
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All the tan wires are connected together and should have battery voltage with the key on run. You know the wires going to the temp switches are good the only way to test the switches is on a overheat condition. The temp and low oil are normally open switches when it overheats or runs low son oil the switch closes and the buzzer sounds. The VRO is normally closed when you turn the key on the buzzer sounds until oil reassure closes the switch (engine running). The grey wire is for the tach maybe racer knows how it works with the VRO? IDK
 
Maybe your problem is at the terminal block on the side of the engine the schematic should show you how to roperly connect the wires. Be real careful everything is wired correct before you turn the key on.
 
Sam110 said:
No Kim haven't tried doing anything with it at this point. Thanks for the MasterTech tip I'll check them out.

Yes and no Joe, the VRO emits a faint tone (as opposed to a strong loud tone) when the oil reservoir leads are disconnected and the 3 wire VRO plug and its TAN wire at the opposite end of its loom is left connected. I can disconnect the VRO's tan wire while leaving the 3 wire plug connected and the faint tone will stop. I am making an assumption that the fault lies within the disconnected oil reservoir circuit which may be effecting the VRO circuit. Both overheat sensors continue to work if tested by shorting out. It seems the overheat sensors operate independently of the VRO / oil reservoir. I'll have to have a look at the float switch in the oil reservoir circuit before I can be certain the VRO itself is not faulty.

Kim, the three wires from the VRO, tan, black and gray ~ the black and gray are the two your describing that operate a 'pressure switch'? They both are connected to the the terminal bar on the starbord side of the engine. I'll have to look at that schematic in the site you referred me to to better understand.
Click to expand...
possibly you have a bad ground to the VRO are you saying the BRP is buzzing or the warning horn is weak?
 
Warning horn is weak Kim. (BRP?) The 'pressure switch' explanation helps. I haven't been running the engine only turning the key to "on". Guess I need to have it running and the weak tone will stop as the switch is pressurized? (thinking out loud) And I'll remove that VRO ground at the terminal block and make sure it is making good contact.

I understand that the temp sensors themselves 'could' be faulty .. that shorting the circuit out only tests the circuit, but I wasn't planning on removing them to test them.
 
Pulled the float switch from the oil reservoir and it seems to be working (visually) so I reinstalled it before realizing I should have tested the circuit open and closed. Checked some prices on a new switch assembly for the tank and I'm just about convinced that I'm going to pull that reservoir and related wiring/tubing, replace the VRO with an aftermarket fuel pump and be done with it. I'll premix all my fuel, and have a simplified less cluttered boat and motor with greater confidence on the water. Only remaining concern by going this route is if the MIXED fuel will have any effect on the canister fuel filter/ water separator?

I checked that Mastertech Marine site Kim and their schematic's are awesome! Had exactly what I needed.
 
Ok, so I have pulled the tank and related hdwr. I was curious about the floats circuit so there was no better time. While the float itself was operating I got no change in readings when the contact disk at the top of the float stem made contact with the metal contacts on either side. I then decided to have a look inside the upper portion of the unit that's affixed to the top of the tank that the float assembly was connected to. Two screws on the underside should expose what lies between the two halves . . . or so I thought. No way! I could not get the halves apart. Determined to open it up to have a look it snapped and came apart piece by piece. Inside I found a clear 'gelled' substance and I could see several 'resisters' or 'diodes' or some such electronics inside. I went no further and remain convinced the issue .. if it were to be positively identified, lies within the 'gelled' electronics of that upper portion of the assembly.
 
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