Water pump - what pressure?

[bloodygazza]

Hi all,

In additional to a tell-tale for the cooling system, I'd like to fit a outboard water pressure gauge to my instruments.
As there are two gauges of suitable scale to do this, 15 psi or 30 psi, I'm wondering what is the maximum pressure that the water pump can supply? Would a 15 psi gauge be high enough?

Thanks,

Gary.

 

[sweezy722]

Re: Water pump - what pressure?

I have a 199 40 and it has a 30 psi gauge but I have never had more than 12 psi. I don't care if it is 8 psi - 12 psi - or 16 psi and long as I have pressure and flow.

 

[pnwboat]

Re: Water pump - what pressure?

What year and model motor do you have Gary? I have a 1988 125HP. At full throttle 5400 RPM's I usually see about 20 - 25 lbs of water pressure.

 

[bloodygazza]

Re: Water pump - what pressure?

It is a 1976 75hp. Fresh pump assembly and water line inlet seal (water tube to adapter plate) so I shouldn't have any leaks ........ I ordered a 15psi gauge just yesterday, thinking I should change that to a 30?

Most of my usage is in "cruise" mode .... average 3500-4000 rpm. I did question the gauge specialist about max. pressure for the 15psi unit, which he recommends not to exceed 60psi!

As it's a case of low being a problem, not high, I might try the 15psi so I see low pressure. It won't break it if I exceed the max, which I may not see very often.

I'm only being picky as I like to try and use the correct full-scale gauge for the application. I have a 6,000 rpm tacho (max motor rpm 5,300), a 15 amp ammeter (max charge/drain 11amp) and think a 15psi pressure gauge is in keeping with the theme. I just like to match the right gauge with the job it has to do.

Thanks for the info.