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zboss · 25-10-2013, 18:28

Hi folks,

My 1986 Westerbeke W46 shows the temp on the panel but does not sound an alarm at overheat.

I assume the sounder on the panel is the same one that sounds when I turn the engine key on, so I know that is working.

The parts catalog lists both a water temp sender and a water temp switch. I'm pretty sure the sender is working, because like I said, the temp shows up properly on the control panel.

Does this mean that the water temperature switch is responsible for sounding the overheat alarm?

Thanks,

Z

**sailorchic34** · 25-10-2013, 19:38

Quote:

Originally Posted by zboss

Hi folks,

My 1986 Westerbeke W46 shows the temp on the panel but does not sound an alarm at overheat.

I assume the sounder on the panel is the same one that sounds when I turn the engine key on, so I know that is working.

Z

On older diesels, generally there is a separate fixed point temp switch that would connect to the high temp alarm. The gauge temp sender is a variable resistor/ thermistor sensor. You'll have single wires going to each sender. Should be near the water pump return line, The line from the engine to the pump as oppose to the line from the pump to heat exchanger. The fixed point high limit temp switch is in many cases the larger of the two sensors....

Newer engines could read the resistance on the temp wire and sound an alarm that way. But old engines had two sensors

zboss · 25-10-2013, 19:43

Quote:

Originally Posted by sailorchic34

On older diesels, generally there is a separate fixed point temp switch that would connect to the high temp alarm. The gauge temp sender is a variable resistor/ thermistor sensor. You'll have single wires going to each sender. Should be near the water pump return line, The line from the engine to the pump as oppose to the line from the pump to heat exchanger. The fixed point high limit temp switch is in many cases the larger of the two sensors....

Newer engines could read the resistance on the temp wire and sound an alarm that way. But old engines had two sensors

Yep... I was able to locate both the sender and the switch. Maybe I'll just go ahead and replace the switch and see what happens. However, with my other mods, maybe I won't have this problem (clean bottom, properly sized prop, and a new heat exchanger).

Saltyhog · 28-10-2013, 14:49

Z, what prop did you settle on? Also, where did you get your new heat exchanger?

zboss · 29-10-2013, 08:28

We went with a 17x9 over the 18x11 that came with the boat. I used the "Digital Prop Shop" to select it based upon our Westerbeke 46. Obviously, if you have a different engine with different RPM needs, your prop would be different.

In regards to the heat exchanger, it's from Lenco. I had Cooks marine remove it for proper fitting, they are called in the dimensions, and the new one should be arriving in the next few days. As soon as I know the model I will let you know but, again, it'll be different unless you have the same engine.

The Lenco cooler was 1/2 the price of the Westerbeke cooler and I think is a better design.

While I am at it I am also replacing my glow plugs, getting my injectors serviced, replacing the thermostat, and also the temp switch.

Saltyhog · 29-10-2013, 09:03

Quote:

Originally Posted by zboss

We went with a 17x9 over the 18x11 that came with the boat. I used the "Digital Prop Shop" to select it based upon our Westerbeke 46. Obviously, if you have a different engine with different RPM needs, your prop would be different.

In regards to the heat exchanger, it's from Lenco. I had Cooks marine remove it for proper fitting, they are called in the dimensions, and the new one should be arriving in the next few days. As soon as I know the model I will let you know but, again, it'll be different unless you have the same engine.

The Lenco cooler was 1/2 the price of the Westerbeke cooler and I think is a better design.

While I am at it I am also replacing my glow plugs, getting my injectors serviced, replacing the thermostat, and also the temp switch.

We have the same engine on the same boat. I'm looking forward to how the new prop works for you. Especially WRT fuel efficiency. Our boat is powered and proped the same yours was. Would not reach full RPM and would get hot (but not overheat) if run over 2500 RPM. I think it's over proped and you've come to the same conclusion.

S/V Antares · 29-10-2013, 09:13

You can easily test the temp switch in a pans of water on the stove if you have a good cooking thermometer. With an Ohm meter (Multimeter) just see what temp it makes continuity as the temp rises. (Or not if it is bad.)