What should my water pressure guage read?(200 merc/30"shaft/1992)

[Kenny Bush]

Does anyone have a good ballpark number, that my water pressure guage should be reading under power. At best, I am seeing 12 lbs. I put a new impeller in recently and it still seems low. The tell tail water seems ok but when I run this CC wide open, I get an alarm. The boat is a 92' Fountain-25'-Center Console-with a notched transom.

 

[edboat]

Re: What should my water pressure guage read?(200 merc/30"shaft/1992)

i run a 1986 175hp Eveinrude and at idle the water pressure is about 1-2 lbs and at WOT it pushes out about 11-12 lbs. It has been about 3-4 years since water pump rebuilt.

 

[robalofish]

Re: What should my water pressure guage read?(200 merc/30"shaft/1992)

I’ve got a 1994 200hp carbureted Mercury 25” according to the Mercury book 12-14 PSI at WOT is just fine. About your alarm which alarm “BEEP-BEEP-BEEP – OIL” or “CONSTANT BEEP – WATER”. <br /><br />RFish <br /><br />

 

[Kenny Bush]

Re: What should my water pressure guage read?(200 merc/30"shaft/1992)

the beep is constant.... so it is temperature..... Fountain mounted the motor with the cav plate about 3 inches above keel. It does have a notched transom.

 

[robalofish]

Re: What should my water pressure guage read?(200 merc/30"shaft/1992)

If you have 12 PSI at WOT that’s fine, now when your running 1000rpm you should have about 5-6psi. If this is correct then I would look at the thermostats should be 2 one each side. If you’re going to open them up, replace them, not worth fooling with them for the price of a set about $15. Another thing when you changed the impeller was the old one in one piece, no missing vanes etc. Sometimes these break off and lodge in the block in strange places like the thermostat openings. Also 3” above the keel is quite a ways out for the engine. Mine have always been even with the keel. Has this been running like this? Is there any way to lower it (move bracket down maybe).<br /><br />Good luck<br /><br />RFish

 

[clanton]

Re: What should my water pressure guage read?(200 merc/30"shaft/1992)

This boat only have one 200 HP engine? I will check my manual for specs tonight, but I think WOT is 12 pounds. I would also check the pressure relief valve. Has the engine always ran hot?

 

[clanton]

Re: What should my water pressure guage read?(200 merc/30"shaft/1992)

12 lbs water pressure 5500 rpms.

 

[Kenny Bush]

Re: What should my water pressure guage read?(200 merc/30"shaft/1992)

Thanks guys..... Sounds like the pressure is right on the money. I still overheat when I run wide open. It only takes about 10 seconds for the alarm to come on..... When I continue to run(after dropping RPMs to 4000) it will go off in about 15 seconds. I posted last year about the cavitation plate being above the keel. About 2/3 of my prop is even with the keel and lower. Everyone said it was fine as long as it was not cavitating. And still it does not cavitate.... I wonder if the water pickup holes are above the keel line at WOT. Also, No the last impeller looked fine. I replace it anyway, and kept the old one as a spare. At first I thought that the 30" shaft was just a long way up to pump the water. Thanks again........

 

[robalofish]

Re: What should my water pressure guage read?(200 merc/30"shaft/1992)

That prop out of the water bothers me but if no cavitation I guess its OK. If your wondering about the water pickup's you could have someone look while under way. Back to the cooling problem, if you are getting the 12Psi when the boat is running WOT then I believe you have enough water just not moving it to the right places. I would check the thermostats, as they or the poppet valve would be the next likely cause. Here again if your going to look at the thermostats change them there cheep.<br /><br />RFish

 

[Hooty]

Re: What should my water pressure guage read?(200 merc/30"shaft/1992)

You might be getting air in the water pick-ups but the pressure gauge should fluctuate if it is. You can try blocking the top water pick-up holes off and that should eliminate any air or try a low water pick-up.<br /><br />c/6<br /><br />Hooty