water pressure guage

[rrossi]

I have a 1978 140 merc straight 6 i need to know how and wear to install a water pressure guage

 

[Chris1956]

Re: temprature sender

Re: temprature sender

A temp gauge is useless on that motor. It will run dead cold most of the time and then overheat, if something is wrong with the impeller/waterpump.

I recommend a water pressure gauge. It will have a few PSI at idle and more at cruise. Monitor the gauge for changes.

 

[RadarRick]

Re: water pressure guage

Hey Chris
The man is asking about water pressure gauge - asking for ideas on installing.

 

[Chris1956]

Re: water pressure guage

Sorry early morning or senior moment....

If the motor has a threaded pipe plug in the cylinder head water jacket, that is the place. If not, remove the black plastic elbow that goes to the telltale and install a brass tee into the threaded port. Now install the hose barb to the gauge on one side of the tee and the telltale elbow on the other side.

 

[donaldboyer]

Re: water pressure guage

Hi, I am looking at installing a Water Pressure gauge on my 1988, 3 cyl, 2 stroke, 90hp Merc.

Am I correct in thinking that I can cut the hose that runs from the engine to the tell tale, install a tee, fit each end of the cut hose on two legs of the tee, and run a hose to the gauge from the remaining leg?

I would assume it doesn't matter where the hose to the gauge reads the pressure as it would be constant all through the system??

Also, do I need a Merc gauge or would a generic suffice? What pressure range should the gauge cover??

Thanks in advance!

Donald.

 

[electricjohn]

Re: water pressure guage

I installed a small gauge in the head up by #1 where the brass plug is (was). Think the thread is 1/8-27 NPT. 7-9 psi @ idle, 14 psi at WOT.

 

[Chris1956]

Re: water pressure guage

Donald it is better to install a brass tee in the cylinder head water jacket, as I described. You will get a more accurate (higher) reading. Now since these motors have so little water pressure, I think accuracy is important.

 

[donaldboyer]

Re: water pressure guage

OK, I'll attach a tee at the head.

What psi range am I looking at for this engine?