Water Pressure Sensor/Alarm

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tonka_boy2

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Feb 28, 2010
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The boat: 1972 Mercruiser, 888

Is there a Water Pressure Sensor/Alarm kit that I can purchase for this engine? I guess what I am looking for is a device that sits inline with the input water hose from the lower unit. The device would sense water flow and an alarm would sound in the event of a failed impeller or other restriction of water flow.

Does such a device exist?

Also, does anyone know where I can purchase a over-heat warning alarm? I fought an over-heating problem with this boat several years ago and now it's no fun keeping my eyes glued to the temp gauge.
 

Bondo

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Re: Water Pressure Sensor/Alarm

Does such a device exist?

Nope,... Not that I know of anyways,...
An Outboard water pressure gauge could be plumbed in though...

The overheat Alarm can be put together using Merc. parts from a newer motor...
It's just the temp Switch that goes to ground, turning on the alarm, when Hot enough...
Unlike the temp Sensor you have now, which is variable grounding...
 

180shabah

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Re: Water Pressure Sensor/Alarm

Merc has a three point alarm (temp, oil pressure, drive lube level) that can be easily addded. Senders just short to ground, so you can add other "inputs" as desired.
Maintain your water pump EVERY year and you should be fine on the waterflow.
 

180shabah

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Re: Water Pressure Sensor/Alarm

Looks like I got beat by bondos finger....
 

Silvertip

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Re: Water Pressure Sensor/Alarm

Head to your local auto salvage yard. Pull an idiot light type temp sensor (nothing more than a switch) and on the way home stop at radio shack and pull out another two bucks for a 12 volt buzzer. 12 volts from the ignition switch to the buzzer, another wire from the buzzer to the sender and you are in business for less than five bucks (10 if the salvage yard are hold-up artists). The sender can be installed anywhere there is an unused port. Use reducer bushings from Lowes, Home Depot or your local Mom & Pop hardware store if the sender is too small for the hole it needs to go in. Go one step farther and buy a large 12 volt panel light at Radio Shack and wire it across the buzzer terminals. Now you have three warnings: The gauge, the light and the buzzer. No excuse for burning down an engine. Actually there is no excuse for that even if you have only a temp gauge because the engine will tell you long before high temp is reached that something is wrong. People tend to pay more attention to the gas gauge than the instruments that are really important.
 

Bondo

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Re: Water Pressure Sensor/Alarm

Looks like I got beat by bondos finger....

Ayuh,... Severely, I'd say,... 15 Minutes of Beat....:D
People tend to pay more attention to the gas gauge than the instruments that are really important.

Amen ST, Amen,....
I bet the percentages are Extremely High, that most boat motors Never get their Oil checked before each outing....
 

Jonezin

Petty Officer 1st Class
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Re: Water Pressure Sensor/Alarm

Actually there is no excuse for that even if you have only a temp gauge because the engine will tell you long before high temp is reached that something is wrong. People tend to pay more attention to the gas gauge than the instruments that are really important.

I have a 88 merc 135 v6 #B278681.
My family has had this boat since new, now i have it. I did the grounding test nothing happened. I ordered new thermostats and water pump kit. I have a leak in the exhaust plate cove got those gaskets ordered. my temp runs 180-190 at 3500 rpm cursing speed. How close to danger am I?

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

My dad gave my brother this boat a few years ago and he didn't give a **** about I've loved it from day one. So it has mostly sat in his shop. Well this year he pulls it out wont fire he has all kinds of work done to it, carbs rebuilt new stator injector and fuel pumps rebuilt new coils, everything shy of pulling the head. Wont fire, no spark. So he calls me ask me if I want it, hell yes its my dads Sea Ray Servile if for no other reason. I get it check it out change 2 fuses on the motor and one under dash fires right. Aint life sweet.

But I'm worried she running to hot, everything I could fine calls for 140 degree thermostats,40 less then where we at now. water is very hot out the pisser port. What you think?
 

Haut Medoc

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10,645
Re: Water Pressure Sensor/Alarm

I have a 88 merc 135 v6 #B278681.
My family has had this boat since new, now i have it. I did the grounding test nothing happened. I ordered new thermostats and water pump kit. I have a leak in the exhaust plate cove got those gaskets ordered. my temp runs 180-190 at 3500 rpm cursing speed. How close to danger am I?

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

My dad gave my brother this boat a few years ago and he didn't give a **** about I've loved it from day one. So it has mostly sat in his shop. Well this year he pulls it out wont fire he has all kinds of work done to it, carbs rebuilt new stator injector and fuel pumps rebuilt new coils, everything shy of pulling the head. Wont fire, no spark. So he calls me ask me if I want it, hell yes its my dads Sea Ray Servile if for no other reason. I get it check it out change 2 fuses on the motor and one under dash fires right. Aint life sweet.

But I'm worried she running to hot, everything I could fine calls for 140 degree thermostats,40 less then where we at now. water is very hot out the pisser port. What you think?
I think this is the I/O forum & you need to be in the Mercury OUTBOARD forum to get the right answer....;)
 

Jonezin

Petty Officer 1st Class
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Re: Water Pressure Sensor/Alarm

Thanks guys, will be more mindful of my posting areas.
 

elkhunter338

Master Chief Petty Officer
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Jun 27, 2009
Messages
818
Re: Water Pressure Sensor/Alarm

Go to summit racing and buy a electric fan temp sensor that turns an electric fan on. I installed this on my boat so an alarm will sound. Instead of the switch turning on a fan it turns on my idot light and buzzer. These I also bought at the autoparts store. Also hooked into the same buzzer and light is a low oil pressure switch.
However do not use any brass fitting/pip on the oil pressure switch, the vibration of the engin may crack the brass fitings, use steel.
 

Jonezin

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Re: Water Pressure Sensor/Alarm

I looked on there tonight and all I could find was 170 degrees or higher which one did you get?
 

elkhunter338

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Re: Water Pressure Sensor/Alarm

I used the 30111 model on @ 185 deg. I have installed a closed cooling system with a 160deg thermostate. 185 deg. will warn you before damage has occurred even with a 140deg thermostate in a fresh water cooled system.
My thermostate housing had a pug in it where the thermo switch plumbed right in. The switch grounds so you can test your light/buzzer by grounding the wire as if the switch closes.
 

Jonezin

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Joined
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Messages
200
Re: Water Pressure Sensor/Alarm

I looked at that one (the painless one), but i could not determine if it needed a relay or not i can make a harness. I'm leaning towards Perma-Cool 19003 170 degree on, just 185 scares me on a 140 thermo. I ordered a poppet rebuild kit.
what you think?
 
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