What's this called

ericcarr2000

ericcarr2000

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Mar 19, 2010
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While winterizing my 90 7.4 motor, I took off my thermostat housing. I disconnected the 2 wires that go to it and noticed that part of the round plastic part under the wire cracked and fell apart. I believe it was located on the port side, not 100% sure though. Can someone explain what this is called, not sure if it's a warning or a temp switch?
 
alldodge

alldodge

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ericcarr2000 said:
While winterizing my 90 7.4 motor, I took off my thermostat housing. I disconnected the 2 wires that go to it and noticed that part of the round plastic part under the wire cracked and fell apart. I believe it was located on the port side, not 100% sure though. Can someone explain what this is called, not sure if it's a warning or a temp switch?
Click to expand...

If it looks like item 11 in link below it is your water temp sender. Will either be 3/8-18 (806490T) or 1/2-14 (97258A1)

http://www.mercruiserparts.com/Show...bdesc=WIRING+HARNESS,+ELECTRICAL+AND+IGNITION
 
alldodge

alldodge

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ericcarr2000 said:
I have 2 of them. The one I need has a much wider end on it.
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One is a switch and the other is a sensor. Your year motor should have single studs on the sensor/switch on them. One is a switch and the other is a sender. In my previous post it list a 1/2 diameter item part number 97258A1 , this should be the one you need, because the other is 3/8 diameter. Trying to find out which is which but have not found info yet. If one is NT 3/8 and the other 1/2, then you need the 1/2
 
Fun Times

Fun Times

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ericcarr2000 said:
That's exactly what it is, only mine was black instead of red. Thanks
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Is your engine cooling system standard/open or closed/antifreeze.

If the switch is OEM and black like Merc part 87-86080 then the temp to sound the horn should be right around 220 degrees. The red is set to sound around 196 degrees. The aftermarket temp switches from Sierra are set for 200 or 240 depending on what one you have. You'd have to know the thread sizes as well before just changing temp settings/switches. There's also a temp switch for engine models that utilize a transmission.

http://www.bing.com/images/search?q=87-86080&FORM=HDRSC2
https://www.perfprotech.com/mercrui...catalog/audio-warning-system/assembly/906/300

This is just some general info to know in case anyone is interested is all.
 
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