Pressure gauge on dash

[truhl_58]

I have a 1075716 MERCURY 1986 75 Hp motor. There is a pressure gauge on the dash ( 0-30?? psi) what is the gauge for and what should it be running at ? New boat and no manual. Thanks for the help.

 

[Chris1956]

Re: Pressure gauge on dash

That gauge measures the pressure of the cooling water in the motor is a real good way to tell if the motor is running cool. Figure 5 PSI at fast idle or higher. 10 PSI at cruise speed.

 

[Char-K-Tac]

Re: Pressure gauge on dash

What does your gauge read currently at WOT and high idle?
I ask because sometimes they get plugged with debris and if you disconnect the tubing at the back of the unit and run the engine it can clear out any gunk in the tubing and the gauge will sometimes come back to life. And sometimes it won't, and then it's time for a new gauge, as is the case with my Merc Opti.

 

[truhl_58]

Re: Pressure gauge on dash

0-1 at idle and 5 max at cruise. Warm to cool water out the pee hole and a good strong stream. Do you think there is a problem?

 

[Char-K-Tac]

Re: Pressure gauge on dash

No I don't think your motor has a problem and the 'telltale' is steady, yes?
once the boat is up to operating temp the water out should be consistently warm to hot- showing it is passing through the engine's water jackets and extracting heat.