Warning Buzzer

[tysdad2010]

I have a question...I know there is a warning buzzer for the oil sensor i beleive correct me if i am wrong... but does that also work for when the engine runs hot? or you have to add that your self?

My engine had the oil injection deleted so I mix my oil with my gas so I dont have to worry about a oil pump going out or whatever I guess?

However I have NEVER heard my buzzer go off in the 4-5 years me and my family have owned this bass boat...and I have spotted the buzzer it is down by my foot by the pedal...can someone maybe chime in and help me out on this one...thanks

 

[Dave1027]

Re: Warning Buzzer

What motor?

 

[tysdad2010]

Re: Warning Buzzer

1985 mercury blackmax 150

 

[woody66912]

Re: Warning Buzzer

With the key in the (on) position ground the wire harness side of the tan lead that goes to the temp sender in the head. You should get a solid horn.

 

[tysdad2010]

Re: Warning Buzzer

With the key in the (on) position ground the wire harness side of the tan lead that goes to the temp sender in the head. You should get a solid horn.

Can explain more in depth please? on the motor or by the horn? the tan wire will be located...and once I have done that ....what does that indicate to me?

 

[Texasmark]

Re: Warning Buzzer

Can explain more in depth please? on the motor or by the horn? the tan wire will be located...and once I have done that ....what does that indicate to me?

On the rear of both cylinder banks of your engine are OT sensors. They can be located by a tan or a tan/lt blue stripe wire coming from them. I think the port side has a tan and starboard a striped wire.

The OT sensor shorts out at about 195F grounding the wire attached to it. This puts a ground on the low side of your OT horn and causes it to activate. So to do what woody suggested, go to the sensor(s), follow the wires to wiring harness connectors and remove the wire(s). Turn you ign sw to ON and with a piece of wire to the engine block, stick the loose end in the connector where the wires you removed were plugged. You should get a solid tone with either wire when doing that.

Mark

 

[tysdad2010]

Re: Warning Buzzer

On the rear of both cylinder banks of your engine are OT sensors. They can be located by a tan or a tan/lt blue stripe wire coming from them. I think the port side has a tan and starboard a striped wire.

The OT sensor shorts out at about 195F grounding the wire attached to it. This puts a ground on the low side of your OT horn and causes it to activate. So to do what woody suggested, go to the sensor(s), follow the wires to wiring harness connectors and remove the wire(s). Turn you ign sw to ON and with a piece of wire to the engine block, stick the loose end in the connector where the wires you removed were plugged. You should get a solid tone with either wire when doing that.

Mark

ok cool thanks very much for explaining i will try this once i get the boat back and let yall know

 

[Dukedog]

Re: Warning Buzzer

1985 mercury blackmax 150

Just tha tan wire on tha starboard head. Might be "in" a clear plastic sleeve. Port is for temp guage if it even has one............

 

[Texasmark]

Re: Warning Buzzer

Just tha tan wire on tha starboard head. Might be "in" a clear plastic sleeve. Port is for temp guage if it even has one............

Son had one and it had the wires as I stated; that is where I learned of them. Since he had a thermostat in the top of each bank of 3 cylinders, if a stat stuck closed (which they will do) in one bank, that bank could overheat.

Mark

 

[Dukedog]

Re: Warning Buzzer

Hmmmmmm. Never seen that before. One sure way to tell on that motor is heat horn sensor will be a bi-metal exposed spring and NO ground wire. A temp guage sensor WILL have a ground wire............

 

[Texasmark]

Re: Warning Buzzer

Hmmmmmm. A temp guage sensor WILL have a ground wire............

Nope!!!!!!! Didn't on his 150 and doesn't on my 90. Sorry!!!!!\\

The sensor makes the ground in it's hole. If it wasn't 105 outside and the fact that I have had my bath and supper, I'd go out and take a picture of it and figure out how to post it to prove it to you!!!!!!!!!!!!!!!!!

Mark

 

[Dukedog]

Re: Warning Buzzer

We're sayin' tha same thing I think. If tha motor has two ONE wire sensors they both will be heat horn sensors. What I'm sayin is that if there's one on each side someone has added tha heat horn sensor to tha port side. Production V6's only came with one (one wire) heat horn sensor on tha starboard side. Tha guage sensor (two wire) installed in tha port head came with optional temp guage. Thats tha reason I brought up tha difference in tha type sensors...........

 

[Texasmark]

Re: Warning Buzzer

We're sayin' tha same thing I think. If tha motor has two ONE wire sensors they both will be heat horn sensors. What I'm sayin is that if there's one on each side someone has added tha heat horn sensor to tha port side. Production V6's only came with one (one wire) heat horn sensor on tha starboard side. Tha guage sensor (two wire) installed in tha port head came with optional temp guage. Thats tha reason I brought up tha difference in tha type sensors...........

I wish his engine was here but it's not. Today I took pictures of my 90 showing my OT mounting and a 1/8 brass pipe plug in the water jacket where one could remove it and install a pressure sensor or temp gauge or whatever.

I'm going to diddle with it tonight and tomorrow and see if I can get them uploaded. Maybe in the future it might help someone.

On the subject, as I recall I found it interesting that on his engine one sensor had a solid tan wire and the other tan with light blue stripe. Didn't understand the rationale there.....but I didn't design the thing so who knows.
-----------------------------
Update: I just got my manual out for my 90 triple and looked for the tan and tan/blue wires that came through the engine to the remote control connector. Since these controls run a lot of Mercs engines they share commonality.

I was in my engine today and noticed that I had an unterminated tan wire. The wire to my OT sensor is tan/lt blue stripe.

In looking at the wiring harness for the Commander 2000 remote control in my service manual (the side mount without the big black button which is the 3000), it has no tan on any pin but it does have a receptacle on a tan wire adjacent to the connector at the engine end of the wiring harness. The connector does have tan/lt blue stripe on pin 3 which is the OT warning wire.

I made a note in my manual that the tan wire, being added to the wiring harness for the Commander 2000 with one end at the wiring harness in the engine and the other at the control box is for: ENGINE TEMP SENDING UNIT TO DASH TEMP GAUGE.

So sir, that supports your theory and as you surmised the previous owner of my son's engine did what you theorized and I was in error. This is why I give my references when I say something giving credit where it is due and shame on you (me) where it is due too. Shame on me. Grin......but I didn't know any better.

So, I guess if one stat sticks shut the volume of water through the engine would be half the normal flow and over time it would/cause the engine to reach the 195F required to activate the OT sensor.....that is if the engine were running at low speed for an extended period of time. Otherwise above 2500 rpm it would open the pop off valves and cool things off.

My apologies.

Mark

 

[Dukedog]

Re: Warning Buzzer

Thank you Mark. I can understand how Mother Merc can get confusing with some of tha things they do and especially what other folks can do to them. Plus I have seen a lot of things come outta Wis. that didn't fit tha "normal" criteria for a peticlur motor. Guess it was "put on what ya got handy George" as came down tha line. I know they do that at tha High Performance place (use to anyway). Here's a little of my V6 back ground. Started with tha purchase of 2 in 1976. Since, I have owned, modified, blown up, fixed and/or junked just about every variation of Production and High performance 2.0. 2.4, 2.5 Merc/Mariner V6 powerhead ever put on tha market excluding tha Opti's (which won't do what I require). Even some European models, up to my latest 2007 ROS 280 (which some might say they didn't make). I do NOTHING but these Merc/Mariner V6 motors for myself and a few friends only (as a hobby).

Thanks again and fully understand...........

 

[Texasmark]

Re: Warning Buzzer

Thank you Mark. I can understand how Mother Merc can get confusing with some of tha things they do and especially what other folks can do to them. Plus I have seen a lot of things come outta Wis. that didn't fit tha "normal" criteria for a peticlur motor. Guess it was "put on what ya got handy George" as came down tha line. I know they do that at tha High Performance place (use to anyway). Here's a little of my V6 back ground. Started with tha purchase of 2 in 1976. Since, I have owned, modified, blown up, fixed and/or junked just about every variation of Production and High performance 2.0. 2.4, 2.5 Merc/Mariner V6 powerhead ever put on tha market excluding tha Opti's (which won't do what I require). Even some European models, up to my latest 2007 ROS 280 (which some might say they didn't make). I do NOTHING but these Merc/Mariner V6 motors for myself and a few friends only (as a hobby).

Thanks again and fully understand...........

WOW. I guess you DO know what you are talking about. Thanks,

Mark