Temp and Oil Warning System

[Jonezin]

I know this topic has been beat to death but I need a clear picture painted for me.

I have a 88 merc 135hp v6 #B278681.
My family has had this boat since new, now i have it. I did the grounding test for the buzzer nothing happened. my temp runs 180-190 at 3500 rpm cursing speed. But I get no alarm

I'm going to put in a buzzer , but i'm a little confused. There is only 1 wire coming from the sensor that goes to this screw, how do I do this, do I take that lead off the screw and splice it for the buzzer. If you have a diagram that would help me a lot.

I have an oil injector that I still use (I know but it works for me), it has been rebuilt never has ever given us any problems. I still would like some kind of warning system on it in case it does flip out. I was told to get an electric fan control switch and wire that to a buzzer. But i can only find one that kick on at 170 degrees I'm running 140 T-stats and it don't do nothing for the oil warning. I keep it full hell it holds 5 gallons, but still things happen.

I have a water pressure gauge on order, we ride a congested lake so I cant spend a lot of time watching the dash I need something audible. I understand my gauges, I also understand the sound of my engine as well.

Again I know this has been beat to death, but i cant find anything in plain English. I'm experienced boater who has started to get their hands dirty due to economy cheaper to fix it yourself. If anyone mind helping me with this I greatly appreciate it.

 

[achris]

Re: Temp and Oil Warning System

More than happy to help....

I know this topic has been beat to death but I need a clear picture painted for me.

I have a 88 merc 135hp v6 #B278681.
My family has had this boat since new, now i have it. I did the grounding test for the buzzer nothing happened.

Do you get the beeps when the key is turned ON? If not, then the buzzer in the control box may be faulty.. When you say you did the ground test for the buzzer, exactly what did you do?

my temp runs 180-190 at 3500 rpm cursing speed. But I get no alarm.

That's ok....

I'm going to put in a buzzer , but i'm a little confused. There is only 1 wire coming from the sensor that goes to this screw, how do I do this, do I take that lead off the screw and splice it for the buzzer. If you have a diagram that would help me a lot.

I have an oil injector that I still use (I know but it works for me),

The Merc oil injection system is very reliable. I don't understand why there is a scream to remove them. (Well, I do, it's because of the high failure rate of the Johnson/Evinrude 'VRO' systems, dreadful things!!)

I still would like some kind of warning system on it in case it does flip out. I was told to get an electric fan control switch and wire that to a buzzer. But i can only find one that kick on at 170 degrees I'm running 140 T-stats and it don't do nothing for the oil warning. I keep it full hell it holds 5 gallons, but still things happen.

I have a water pressure gauge on order,

Good....

we ride a congested lake so I cant spend a lot of time watching the dash I need something audible. I understand my gauges, I also understand the sound of my engine as well.

Again I know this has been beat to death, but i cant find anything in plain English. I'm experienced boater who has started to get their hands dirty due to economy cheaper to fix it yourself. If anyone mind helping me with this I greatly appreciate it.

ok... Cooling system first...

The cooling system operates in 2 modes. At low engine speed it's in 'thermostat' mode. The cooling water pressure isn't high enough to open the poppet valve, so the thermostats have temperature control. This is done because 2 strokes need to be run quite warm at lower engine speeds to help reduce plug fouling.

At higher engine speeds the water pressure is higher and so the poppet valve is forced open and the water is now 'full flow' and the engine is cooled down much more....

Buzzer... You should already have a buzzer in the control box. The tan/blue lead coming from the sensor to the terminal block carries the current from the buzzer. When the temperature is too high, the switch closes and completes the circuit for the buzzer, and you hear it... or should.

To test the buzzer, turn the key to ON, get a short length of wire and touch one end to bare metal on the engine block (the ground plate for the electrics is good) and the other end to the tan/blue lead.... Buzzer should sound...
No sound, replace buzzer in control box, or fault find the circuit....

You have circuit diagrams?

Chris........

 

[Jonezin]

Re: Temp and Oil Warning System

Well hello once again chris, i have few minor but important issues

No beeps when key is turned on, my brother had a new control shifter put in it one of those Mercury 4000 Gen II Panel Mount Boat Remote Control, I cant find no diagram for it. there was a brown wire just laying there not connected to anything under the dash. I 'll test it today it does seem to come from the control box at least that's where it feels like its coming from.

The ground test I did was, clip one end on the wire coming from the sensor to the ground plate.

I have a new poppet rebuild kit on order, but the outer poppet plate looks new. My brother has this motor rebuilt everything shy of pulling the power head

You have circuit diagrams? NO

So that 170 switch would be ok then?

 

[achris]

Re: Temp and Oil Warning System

Well hello once again chris, i have few minor but important issues

I wouldn't call no buzzer a 'minor' issue.

No beeps when key is turned on, my brother had a new control shifter put in it one of those Mercury 4000 Gen II Panel Mount Boat Remote Control, I cant find no diagram for it. there was a brown wire just laying there not connected to anything under the dash. I 'll test it today it does seem to come from the control box at least that's where it feels like its coming from.

Is the wire brown or tan? (Tan is lighter, and yes, it makes a difference)

The ground test I did was, clip one end on the wire coming from the sensor to the ground plate.

Good, correct test. With the key ON?

I have a new poppet rebuild kit on order, but the outer poppet plate looks new. My brother has this motor rebuilt everything shy of pulling the power head

You have circuit diagrams? NO

So that 170 switch would be ok then?

No. I think you'll get false alarms with a 170 switch.

Ok, the new control box... Panel mount is not for outboards (as a rule)... It's for stern drives. Don't worry, it won't hurt the engine. It's just that panel mounts don't have the electrics inside them. So, what's to do with what you have?

Where does the harness from the engine go? Up under the dash? If it does, we may be able to get the correct warning horn for you and mount it under the dash (with all the other wires) and wire it in so it all works the correct way....

If I'm correct in the way I see the setup, then all you have to do is find the purple wire that comes from the key switch (there should be a red, a purple and a yellow/red coming from the key switch). We connect one wire of the the warning horn (the +) to the purple wire and the other (the -) to the tan/blue wire from the engine. The part number for a warning buzzer is -816492A1 and is available from www.mercruiserparts.com for $37.24, or your local Merc dealer....

Chris..........

 

[Jonezin]

Re: Temp and Oil Warning System

Is the wire brown or tan? (Tan is lighter, and yes, it makes a difference) as best as I can see its tan

I see those 3 wires the purple red and yellow and red
for testing purpose can I run leads to the boat horn to the purple and that tan/blue wire from the engine ?

under the dash there is NO tan/blue wire from the engine, do i need to run one?

Good, correct test. With the key ON? YES I just did it again with my test light, i have a circuit at the motor now just finding that wire under the dash. It leaves the motor as tan i got some hunting to do.

Also I just found that i have no t-stats in I did a compression test it all held 121's my gauge only goes to 125. Not 1 t-stat. Nice... My brother the big shot. still need a buzzer.

 

[Jonezin]

Re: Temp and Oil Warning System

Ok chris I found a small module under the dash that has a small 12 volt lead. I gave it power and grounded at the motor. It works, boiling water now to be sure, and have a reference point.

 

[Jonezin]

Re: Temp and Oil Warning System

Forward is all done.... New fuse block in. Got beep when key is switched on 2 beeps when off. just waiting on the mail man now.

 

[Jonezin]

Re: Temp and Oil Warning System

A couple weeks ago I was on a search mission to find out why the warning buzzer was not buzzing. Found out why. My controls was replaced and it was replaced controls for a stern drive so they added a alarm buzzer moddual. Today I put in 2 new T-stats 143 degree per spec sheet. New cover plate gaskets, torqued no leaks there. Head gaskets are leaking now.

So my problem is my buzzer is going crazy now. She is holding 141 on the nose. not the 180-190 it was doing. Also the power wire for this buzzer was not hooked up when I found it. Are these alarms set at a different range on stern drives then outboards and causing my alarm to not shut the f up?

Thanks for any help

 

[achris]

Re: Temp and Oil Warning System

The setting for the alarm is controlled by the sender switch in the engine... not the buzzer itself. If the alarm is on continuously, then remove the wire from the sender. If it still buzzing, you have a wiring fault (or a short in the wire that goes to the sender). If it stops, replace the sender switch.

Chris.....

 

[j_martin]

Re: Temp and Oil Warning System

The setting for the alarm is controlled by the sender switch in the engine... not the buzzer itself. If the alarm is on continuously, then remove the wire from the sender. If it still buzzing, you have a wiring fault (or a short in the wire that goes to the sender). If it stops, replace the sender switch.

Chris.....

If it's a normal V6, the overtemp switch is on one head, and the temp gauge sender is on the other.

One could be hotter than the other.

just sayin'
John

 

[Jonezin]

Re: Temp and Oil Warning System

I'll do that as soon as it stop rain and let you know what happened

Thanks again

 

[achris]

Re: Temp and Oil Warning System

If it's a normal V6, the overtemp switch is on one head, and the temp gauge sender is on the other.

One could be hotter than the other.

just sayin'
John

Good point. The sender for the gauge is in the port head and the wire is tan/blue. The temperate warning switch is in the starboard head and has a black wire running to a terminal block with a tan wire on it.

Chris.......

 

[Jonezin]

Re: Temp and Oil Warning System

port head and the wire is tan/blue.Chris.......

I thought that was the alarm sender, and its on the starboard side
On the port side is the temp sender and its tan.

Ok I disconnected one still buzzing, then the other still buzzing. Took them both off still buzzing. So I'l going to take that buzzer moddual wiring apart and check make sure its right.

Temp gauge reacts when I disconnect and reconnect it.

side question, my pisser port hasnt been as strong as I would like so I changed the whole thing base plate and all. And it still not all that strong not much different from before. I found both head gaskets was tweaked a little and the they are leaking one is worst then the other. Would that be the reason for weak to shallow pisser port? or that damn poppet ?

 

[sschefer]

Re: Temp and Oil Warning System

I thought that was the alarm sender, and its on the starboard side
On the port side is the temp sender and its tan.

Ok I disconnected one still buzzing, then the other still buzzing. Took them both off still buzzing. So I'l going to take that buzzer moddual wiring apart and check make sure its right.

Temp gauge reacts when I disconnect and reconnect it.

side question, my pisser port hasnt been as strong as I would like so I changed the whole thing base plate and all. And it still not all that strong not much different from before. I found both head gaskets was tweaked a little and the they are leaking one is worst then the other. Would that be the reason for weak to shallow pisser port? or that damn poppet ?

The port side has the sender. The starboard side has the switch for the buzzer. The port side sender affects the gauge. The starboard switch should have no affect on the gauge.

If you have a std configuration (not race) the stbd thermostat outlet should cross over to the port and then run down to the exhaust plate. The tell tale should tee into the down tube from the port thermostat housing. There are small by pass holes in the thermostats and you should have very low flow out the tell tale until the thermostats start to open. The tell tale flow should increase as your engines temp rises to 143 degrees at which point the thermostats should be wide open.

When the engine RPM reaches about 2000 the poppet will begin to open due to the increase in water pressure out of the water pump. Most of the water volume will be directed through the larger poppet opening rather than the thermostats. This will reduce flow out of the tell tale but at the same time increase flow through the engine.

When the higher flow rate exists it is common for the engine temp to drop below 143 degrees and cause the thermostats to begin to close thereby further reducing the flow out of the tell tale.

The old standby of a good strong tell tale being a good thing is still valid but there are new rules when you own a V-6.

On race motors you typically run washers in place of the thermostats and run separate discharge tubes down from each head and out through the lower cowling. I don't recommend you do it to a fishing motor that you run in the winter because it can result in cold seizing if the water temp gets below 40 degrees.

Heres, the standard configuration for a 2.0L -

 

[j_martin]

Re: Temp and Oil Warning System

If the oil alert module fails, it can cause a continuous beep. It is also connected to that circuit.

 

[Jonezin]

Re: Temp and Oil Warning System

I have that same set up I'll take some pictures tomorrow. But for the most part is should be fine it gets strong when I goose it, I just thought that was the poppet opening.

oil alert module is new, I checked to make sure it had oil. Well I'll tinker with that 2 and see what happens.

Thanks guys

 

[achris]

Re: Temp and Oil Warning System

....oil alert module ....

Right, now we getting somewhere.... I was having trouble because the circuit diagram in the Merc service manual for your engine DOESN'T show any oil injection components. I have the manual that covers 1979-1988 and 1993-2000, but I'm missing the one in the middle. So with that in mind I'll post up the circuit for a 135 that DOES have the oil injection components, it's not your engine but the bits we are interested in are the same.

A quick description of the oil injection monitoring system may help (use the numbers to identify the component in the circuit drawing)...

The oil warning module (3) takes in three signals. One, in the form of a pulse, (usually) from the ignition coil (22) (at the pack end) for #2 cylinder. That would be a green wire. Another pulse from a rotational sensor (6) mounted on the oil pump (it has a white wire, a black wire and a lt-blu/wht wire). The third is a light blue wire from the oil level sensor (4) in the internal oil tank cap.

The module measures the rotational pulses from the pump with the ignition pulses to make sure the pump is turning at the right speed. if there is a discrepancy will should give short beeps, about 1/2 second. If the oil tank level falls then the signal is long beeps.

The overheat warning doesn't go into the oil warning module, but it is wired in parallel, so if you get an overheat the buzzer will give a continuous tone.

The big thing for you is to take the oil warning module out of the circuit (for testing ONLY). The wire from the temperature switch (15) goes to a terminal block (14). There it should join with two tan/blue wires. One of those wires goes to the buzzer and the other goes to the oil warning module.

Remove both the tan/blue wires from the terminal block and hold them away from the engine block. Turn the key ON (don't start the engine). You should have NO buzzer. If you do, then you probably have a problem in the harness.

OK, no buzzer. Touch the tan/blue wires to the engine block. One of them should make the buzzer sound. That one is the one that goes into the harness to the buzzer. The other wire goes to the warning module.

Reconnect the harness tan/blue to the terminal block. Still no buzzer? good... Now connect the temperature warning switch onto the terminal block. If the buzzer starts, the sensor is faulty. If not, all is still good. Now reconnect the warning module wire. Buzzer starts... faulty module or oil tank cap.

Chris............

 

[Jonezin]

Re: Temp and Oil Warning System

I guess its good evening to you,

Thanks for that trouble shooting guide will work on that later today and get some pictures going. I DO NOT HAVE A CONTINUES BEEP, ITS INTERMITTING ABOUT EVER HALF SECONDS LIKE YOU SAID. I know its getting oil because all of the smoke. Like I sad before the modual is new. I opened the cap and is full.

Got to get back to work, I'll let you know what happens tonight well for you in the morning.

 

[achris]

Re: Temp and Oil Warning System

The module could be crook out of the box. We just fixed a trim problem on here for a guy who put a new solenoid in... it was faulty. He put another new one in and the problem was fixed... NEVER assume because it's new it's working....

Chris............

 

[Jonezin]

Re: Temp and Oil Warning System

Well that sucks no return on those parts and I believe mine is bad. I went through that process and the beeping started with the warning wire was hooked up. I even disconnected the the cap wires. Still beeping. Could it be the pump?, but the tank is full and my holding tank is showing 2 gallons.

I'm posting some pics of my motor.

What now, a new one is going to have to wait a couple of weeks unless somebody got one laying around they don't need. Can I run it with out it until I get one. Mom is coming in next weekend and she wants to go out for a spin.



Starboard, alarm sender





Everything over here is new and rebuilt



Port, the wire unhooked is for temp gauge
As you can see the is nothing in the head


Thanks guys


I just found this The part number is 41470A3, the box is an A27 version he said it will work on mine. The modual on mine has "A24" at the end. You cant bet free but if it wont work its no good.