Temperature Sending unit

[markhoekstra]

I have a 1982 50HP merc (S/N in the 60,000 range). It has a brass bolt between top and bottom spark plugs where I believe the temperature sending unit is supposed to go. I want to hook up the temp send, but am not sure which one to get. Does anyone know which one I need or where I can go to look it up?

 

[Chris1956]

Re: Temperature Sending unit

Does that Merc have a thermostat? If so, you might try a temp gauge. The 'stats open at 140*, so a gauge that reads from 120-240 is good.

A water pressure gauge is a very good idea instead.

 

[markhoekstra]

Re: Temperature Sending unit

I'm not sure if it has a thermostat. Is that something that is externally visible? I'm hoping to get it hooked up to a temperature gauge so I can monitor it more accurately (vs. just the horn when there is a problem.)

 

[Chris1956]

Re: Temperature Sending unit

Go on the Crowleymarine.com web site and look up the motor by year and HP, and see if it has a stat. Most inline Mercs of the 60s 70 and 80s do not.


A water pressure guage is the only choice (IMHO) for an statless inline.

 

[markhoekstra]

Re: Temperature Sending unit

I haven't been able to find anything in the drawings to show a thermostat or a temperature sending unit. The bolt that I thought was the right place is called a "pipe plug / cylinder block cover" and is #9 in the drawing below. Where would I look for the water pressure gague / sending unit?