Yamaha V6 Excel XG 1988 - Weird Buzzer Alarm

[Woodeneye]

Apples and Oranges but I've replaced them on all my older Mercs for the same reason. My hot horns would start to randomly chirp and then start sounding steadily and then stop and start again for no reason after completely checking all systems for oil and temp issues without any findings including replacing the keyswitches. The new modules fixed the problem. Both of my twin 115's were doing it within a month or so of one another. Mine were separate modules from the ignition CDI unit so hopefully that is the case for your Yamaha.

When you say "modules" are you referring to the buzzer/alarm unit itself?? Cuz that is separate from the ignition switch panel on mine and easily accessed.

This would be under the engine cowling and may be nothing more than a small black box with some wires coming out of it. Locate the temp switch wire from the cylinder heads and see where that wire goes. It should connect to a module. This has nothing to do with the dash, switch panel or actual horn/buzzer.

OK excellent stuff. I'll get on it today. Thank you.

[Capt. Bob]

OK Wood,
Let's see if we can make some progress.

First, please let us know a little about your model Yamaha. I do know it's a 1988 V-6 model but give me a little more, like displacement and ignition system. I apologize because I left the manual at my office so I can't remember the Yamaha nomenclature for their fancy computer system of that era and again some pics.

In the mean time here are a couple from my old beast.
First, my oil module is located in the CDI (I don't have the fancy computer ign. system)


Yes it's blurred but remember, it's the thought that counts

Please notice the toggle switch located just above the "coil" that supplies power to the spark plug (it has the word OK on it) That switch is used to transfer oil from the remote oil tank to the main tank on the engine. Therefore MY Module is located within the CDI unit (the switch is mounted to the CDI cover). Since yours is older, you may have a separate module (as Futch referred to) located in this general area.



That is my main oil tank (yes it's is currently covered in mold and will remain so till spring )
Your switch may, in fact be located below and to the right of where your tank once was.
Again pics in this area will help.

Lastly, studying the wiring diagram  seems to indicate that a thermal switch for an overheat condition (think water circulation) might trigger the light (and the buzzer of course). I'm not sure it does so....
Can you please post pics of the multi-function gauge(s) you have.

Thanks.

[Woodeneye]

Wow Capt. Bob. Talk about going that extra yard. You are a legend.

Please bear in mind I'm feeling my way here a bit. Diesels I'm a little more versed in. These O/B's are serious voodoo to me    Though I have just taken delivery of a Seloc manual so hopefully I shan't be flying that blind from here on.

I'm struggling to find accurate info re. specs other than it is 225HP. I'll keep looking. Sorry. The manual says (this maybe generic info for all models covered (84-96) in this manual), it has the YMIS which is Yamaha's version of CDI.

I have photos of the motor and gauges and will attempt to upload them tonight (its 1.15pm Friday here now 9.15pm Thursday there), right now I have to race off to a meeting.

Stick with me, I'm not a complete gumby and will, with your, help work this out.

Good man.

Cheers,

Woodeneye.

[Capt. Bob]

Capt. Bob. You are a legend.

In Perrine Fla. maybe...
Here, not so much.

The manual says it has the YMIS which is Yamaha's version of CDI.

The YMIS adds a "computer/microprocessor" to the standard CDI ignition system. While the engines share a similar design CDI, yours has the added features of control to the engine when running my model doesn't have. I make light of this because the YMIS may be playing a roll in your situation but I wouldn't go down that path until you eliminate the e-z stuff.

I have photos of the motor and gauges and will attempt to upload them tonight (its 1.15pm Friday here now 9.15pm Thursday there).

Excellent.

[bondobill]

I had the same engine only it was a 1989 225 Exel, I would quess pretty much the same as a 88

Bob, heres a couple photos of the oil switch from the Exel model, separate switch from the computer





Wish I could be of more help but.....
Just threw the entire engine out 3 weeks ago, darn thing was under my work bench for 4 years

Only time I ever had the alarm sound on start up was after I sucked up some kelp around the lower unit, after removing the kelp and letting engine cool down I restarted engine and the buzzer went for a minute or so until it resets.

Bill

[Capt. Bob]

Thanks Bill.
I'm betting Wood's looks the same. What has me wondering is that he states the middle light (over the oil can) is lit with the buzzer sound. That combination would indicate an overheat condition in progress and a low level in the remote tank. Since he no longer has the tank (but the light is on) I was thinking the module/switch was somehow sending a false signal to the gauge and buzzer.

The oil float switches in the tanks are wired to illuminate the warning lights for low oil situations. The buzzer sounds when the overheat condition appears. That is monitored via the thermal switches. On the YMIS system and additional sensor is present that acts as the fail safe for overheating at high rpm and it too sounds the buzzer but also reduces the engine rpm. It reduces the rpm until the temps return to normal and at that time the buzzer quits. Neat stuff for an older outboard motor.  

Thanks again for the photo.

[Woodeneye]

Here you go Cap'n. As you can see no oil tank..........

[Capt. Bob]

Wood,
Is it possible to get a pic of the tach with the engine running?

Thanks.

EDIT: Ohhhhh..... That's a mid 90's gauge coupled on to an 88 model motor. :o

The warning lighting goes out the window with the oil tanks(and the module/switch) so......

Since the buzzer is going off at start, I would first check both thermal switches and see if either (or possibly both) are functioning(this goes all the way back to the third post by Fitz 8) )

Have you driven the boat at all with the buzzer sounding or is it just on the flush muffs?

You can see one of the switches in this photo (yours) close to the top of the bank. A quick check would be to disconnect the wires and check for non-continuity between the switch wires.

[Woodeneye]

Is this the thermo switch?

[Woodeneye]

Wood,
Is it possible to get a pic of the tach with the engine running?

Thanks.

EDIT: Ohhhhh..... That's a mid 90's gauge coupled on to an 88 model motor. :o

The warning lighting goes out the window with the oil tanks(and the module/switch) so......

Since the buzzer is going off at start, I would first check both thermal switches and see if either (or possibly both) are functioning(this goes all the way back to the third post by Fitz 8) )

Have you driven the boat at all with the buzzer sounding or is it just on the flush muffs?

You can see one of the switches in this photo (yours) close to the top of the bank. A quick check would be to disconnect the wires and check for non-continuity between the switch wires.

Picture of Tach with motor running. Excuse the quality. Its a still from a video.

[Woodeneye]

Wood,
Is it possible to get a pic of the tach with the engine running?

Thanks.

EDIT: Ohhhhh..... That's a mid 90's gauge coupled on to an 88 model motor. :o

The warning lighting goes out the window with the oil tanks(and the module/switch) so......

Since the buzzer is going off at start, I would first check both thermal switches and see if either (or possibly both) are functioning(this goes all the way back to the third post by Fitz 8) )

Have you driven the boat at all with the buzzer sounding or is it just on the flush muffs?

You can see one of the switches in this photo (yours) close to the top of the bank. A quick check would be to disconnect the wires and check for non-continuity between the switch wires.

Yes I have driven the boat with the buzzer sounding once I had established that it wasn't a oil issue & it wasn't overheating. Could a stuck thermostat cause an alarm or is the buzzer purely temp related? For clarity, you don't think this could be a bad buzzer or ignition switch?

[Capt. Bob]

OK Wood,

1: Yes, that is one of the thermal switches (one for each bank).

2: The oil level lights that are "on" in the pic of the tach with the engine running are the same when you just turn on the key so.....

It appears following the wiring diagram for your motor that the yellow wire to the buzzer is hot on start and the pink completes the circuit to ground via the thermal switch(s). Since they are so easy to get at, I would eliminate them first as the cause. If you have an ohm meter, you can check the continuity (you should have none) between the wires to the switch. If not, disconnect the wires (to both switches) and start the engine and listen for the buzzer.

A stuck thermostat, probably would result in an overheat condition, thus triggering the thermal switch but the stat itself has no electrical connection to activate the buzzer.

A bad buzzer?
Well I guess it's possible that the buzzer itself shorted to ground but I'd bet that if a buzzer mechanism failed, it would be in the direction of "no sound".

A shorted wire (pink I'm thinking) could be doing it also.

Ignition switch? I don't see a wiring pattern to suggest that.

This same "pink to ground" wire also is routed back to the "control unit" that is missing from your motor. That allowed the buzzer to sound when the "low oil" level light was triggered. Again, when this stuff was removed and that wire disconnected, where did it end up? Could it be shorting to the motor after lying for some time under the cowling?  

Try unplugging each switch then starting the motor. That's a quick and easy check.

Good luck.

[Woodeneye]

OK Wood,

1: Yes, that is one of the thermal switches (one for each bank).

2: The oil level lights that are "on" in the pic of the tach with the engine running are the same when you just turn on the key so.....

It appears following the wiring diagram for your motor that the yellow wire to the buzzer is hot on start and the pink completes the circuit to ground via the thermal switch(s). Since they are so easy to get at, I would eliminate them first as the cause. If you have an ohm meter, you can check the continuity (you should have none) between the wires to the switch. If not, disconnect the wires (to both switches) and start the engine and listen for the buzzer.

A stuck thermostat, probably would result in an overheat condition, thus triggering the thermal switch but the stat itself has no electrical connection to activate the buzzer.

A bad buzzer?
Well I guess it's possible that the buzzer itself shorted to ground but I'd bet that if a buzzer mechanism failed, it would be in the direction of "no sound".

A shorted wire (pink I'm thinking) could be doing it also.

Ignition switch? I don't see a wiring pattern to suggest that.

This same "pink to ground" wire also is routed back to the "control unit" that is missing from your motor. That allowed the buzzer to sound when the "low oil" level light was triggered. Again, when this stuff was removed and that wire disconnected, where did it end up? Could it be shorting to the motor after lying for some time under the cowling?  

Try unplugging each switch then starting the motor. That's a quick and easy check.

Good luck.

So....It does not appear to be anything to do with the thermo sensors. Nor their wiring. All checks out fine. I even checked the thermo sensors for the hell of it.

So given (?) an alarm only sounds in 3 scenarios,

1. Low oil (can't be, VRO disconnected and system removed) and I now premix.

2. It's not over revving

3. Its not overheating....alarm sounds straight away anyway...

.....it must be a grounded wire somewhere? Right? or am I missing something else that would cause an alarm?

Oh BTW here is the capacity...duh...was staring me in the face.


And also...I've noticed on the fuel gauge that a bar is flashing over the fuel icon on the gauge...another possible cause of the alarm??

Might be time to call in the cavalry.....Im struggling with my skill set...though I've have learnt a heap. Thanks so much for your help thus far.

Cheers,

Woodenye

[Capt. Bob]

it must be a grounded wire somewhere? Right? or am I missing something else that would cause an alarm?

Try disconnecting the pink wire from the buzzer itself. Turn on the key, the alarm should no longer sound.

Now, Turn of the key switch, attach your ohm meter red lead to the disconnected pink wire and touch the black lead to a good ground. Check continuity.
When working properly, you should read "0". If you show continuity then yes, something is causing the pink wire to ground. Now you need to trace that back and see if you can find what/where.

Challenging but not impossible.

Another question. Does your trim gauge work?

And also...I've noticed on the fuel gauge that a bar is flashing over the fuel icon on the gauge...another possible cause of the alarm??

That's a normal alert for a "low fuel" condition. I don't believe it sounds the buzzer but..................
Those are the newer type digital gauges. I don't have my manual at work but let me see what I can find. Don't go to the shop just yet.


Good hunting.

[Woodeneye]

it must be a grounded wire somewhere? Right? or am I missing something else that would cause an alarm?

Try disconnecting the pink wire from the buzzer itself. Turn on the key, the alarm should no longer sound.

Now, Turn of the key switch, attach your ohm meter red lead to the disconnected pink wire and touch the black lead to a good ground. Check continuity.
When working properly, you should read "0". If you show continuity then yes, something is causing the pink wire to ground. Now you need to trace that back and see if you can find what/where.

Challenging but not impossible.

Another question. Does your trim gauge work?

And also...I've noticed on the fuel gauge that a bar is flashing over the fuel icon on the gauge...another possible cause of the alarm??

That's a normal alert for a "low fuel" condition. I don't believe it sounds the buzzer but..................
Those are the newer type digital gauges. I don't have my manual at work but let me see what I can find. Don't go to the shop just yet.


Good hunting.

Cap'n Bob... when I disconnect the pink wire the alarm continues to sound....I've attached a photo of the way the buzzer is hooked up. All look kosher?