What is WATER PRESSURE all about?

BassManDan · Post by **BassManDan** » Thu Jan 15, 2009 4:07 pm

Can someone explain this to me.
Just got a "new" boat (1997 Stratos 295 Pro Elite with a 200 hp Johnson Venom), a nice step above the old Bass Tracker!

On the console I have the psi gauge, but I really have no idea what it means and what I should do.

If anyone out there has a similar boat, please weigh in, your insight would be greatly appreciated!

Thanks all, in advance,
Dan

Joe · Post by **Joe** » Thu Jan 15, 2009 5:15 pm

This guage will help you tell your motor is getting water pressure while running. Example, weeds could clog your water pickup intakes. If that happened you would notice a drop in water pressure, on some motors you could overheat the engine and cause major damage. Its a good idea to carefully monitor water press along with your engine temp while running to prevent damage . It basically goes hand in hand, if you lose your water press{cooling} your temp goes up and overheats the powerhead. I hope this helps.

Joe

Oldschool · Post by **Oldschool** » Thu Jan 15, 2009 5:34 pm

The gage is intended to tell you what water pressure in pounds per square inch "PSI" your OB engines water pump is putting out. That doesn't always indicate what water pressure is being delivered through the powerhead, until the thermostate opens.
At idle the PSI should be steady between 10 to 15 and running it should stay up around 15.
Tom

GW · Post by GW » Thu Jan 15, 2009 5:57 pm

My 225 Optimax doesnt really even move the needle at idle. its in the 10-15 range over 4K RPM. Never had an issue.

Joe · Post by **Joe** » Thu Jan 15, 2009 6:52 pm

I've never seen water press at 10 to 15 at idle on my motor{200 opti} Normally mine will read between 15 to 20 at WOT. I can barley see the needle move at idle, but with my smartcraft guages it normally reads around 2 to 4psi I believe. Bottom line is just gives you an indicator of your cooling system at work, no water press might mean you have a bad water pump impeller, etc. It could also be a clooged sensing line going to the guage. Thats when you will need to observe your tell tale stream that normally shoots out the side of your engine while running.

BassManDan · Post by **BassManDan** » Fri Jan 16, 2009 6:36 am

Excellent! Thanks for the input.

I'll just have to check the specs myself to see what it should be at.

Again, greatly appreciated!
Dan

Oldschool · Post by **Oldschool** » Fri Jan 16, 2009 9:32 am

Good idea to check out your engines manual. Comparing an older Johnson to a newer Mercury Optimax is apples and oranges. The pee hole or exhaust water indicates the water pump is working, not necessarily working propely however. The thermostate doesn't open and let water into the powerhead until the engine warms up enough, a defective thermostate may never open, then your alarm may go off.
Changing the water pump impeller should be an annual engine maintenance item, along with spark plugs.
Good luck with your "pre-owned" rig.
Tom