Water pressure question ?

[pdt]

what is considered normal water pressure ? at say cruising and wide open throttle ?

I have a 1995 60hp evinrude 3 cylinder 56ci, its the later model of the triples , and would like to know what is considered the normal
operating water pressure. ?

I know its best to have a guage as many people have said, and especially if running the engine on jackplate etc. this is being taken care of.

But unless I know what the correct normal pressure is, then having a guage is pointless as it could be much lower than needed.
I don't want to know "what is ok" I want to know what it should be.

some one on here I would presume, knows about the actual pressure required for the optimal water cooling of the engine.

my engine gets a test run hopefully very soon, but my pressure guage has not arrived yet and probably lost in the dreaded post, so will have to
just keep an eye on water coming from the tell tale for now.

once I find the "NORMAL" pressure when the engines are run at recommended transom heights( i.e cav plate level with bottom of boat)
I can then monitor what I am getting when raising the engine and hopefully keep to it, or very close to it.

.

[pdt]

and one of my reasons for asking is that ive seen evinrude water pressure gauges that say from 1993 to 2000 and the gauges read upto 60 psi !!!!
some gauges I have seen show just 30 psi as the max pressure ?

.

[fs5]

mate as long as water is still pumpin out the pisser in a fairly solid stream ,i'd be happy.
dose your motor have an over heat alarm?

[pdt]

yeah I have an overheat alarm and the slow mode feature on my engine, these go off at overheat. but when these alarms go off the engine has already got far too hot to be honest...
I have also got a head temp guage fitted now to keep an eye on as well.
my engine is the later one with the tell tale on the top of number 1 cylinder so at least it shows its up to the top of the block.

there must be a correct minimum pressure though for the engines in a book somewhere ?

.

[TXBOATSHOP]

We put water pressure gauges on every new boat we sell, Most of our engines are V-6 but the WP doesnt change much with the engine size. WP should be in the 20 - 30 PSI range above 3000 - 3500 RPM's. The biggest factors are the type of water pick up on the gearcase, engine height and boat hull configuration. With the boat up and running max speed and jacked and trimmed you should maintain a minimum of about 12 PSI, if you can't do that then you have to fix one of the above. Mercs generally show a little less WP than Evinrude or Yamaha but I would use the 12 PSI as my low number.

[pdt]

That sounds a pretty good answer.
I will now be looking for 15 psi as my minimum. this will be due to me not wanting any overheat situations at all ha ha .
I do like to run on the "SAFE" side of things to be honest.

Now I will look for a guage of upto 30psi to try and keep pressure in the mid to high range, rather than have a 60psi guage that will look low all the time.

just need to find a nice one at the right price ha ha

I take it they are all pretty much the same as far as being accurate to a point !!!
I wont go for cheapo Chinese knock off, but also wont be looking at a high end one, something down the middle will do me fine I think.
I shall look at the faria range and see what they are offering.

[omcstratos]

That sounds a pretty good answer.
I will now be looking for 15 psi as my minimum. this will be due to me not wanting any overheat situations at all ha ha .
I do like to run on the "SAFE" side of things to be honest.

Now I will look for a guage of upto 30psi to try and keep pressure in the mid to high range, rather than have a 60psi guage that will look low all the time.

just need to find a nice one at the right price ha ha

I take it they are all pretty much the same as far as being accurate to a point !!!
I wont go for cheapo Chinese knock off, but also wont be looking at a high end one, something down the middle will do me fine I think.
I shall look at the faria range and see what they are offering.

If you have a pitot style speedometer, you can use that as your water pressure gauge. You can look up at what water pressures correspond with the speed on the gauge. That's an alternative to use for testing if you have it already.

5 PSI = 20 MPH
11 PSI = 30 MPH
19 PSI = 40 MPH
30 PSI = 50 MPH

roughly.

[pdt]

Now that's not a bad idea.
the pitot style is exactly a pressure guage like you say.

ill have to see if ive still got one hanging around .

I like that, due to being a cheap alternative to give it a try.

[Fastjeff57]

That high! Wow, that's a surprise. The raw water pumps on my Chrysler 36 V-8s only produce about 10 psi at 3,000 rpms.


Jeff

[omcstratos]

That high! Wow, that's a surprise. The raw water pumps on my Chrysler 36 V-8s only produce about 10 psi at 3,000 rpms.


Jeff

Yeah, I have the 3 blade style water pump on a 2cyl OMC and it makes between 10 and 16psi on plane

[pdt]

if your running a Chrysler v8 and the water pressure from raw pump is only 10psi you probably have a closed loop system with heat exchanger.
that way your just using the low pressure high volume for mainly the exhaust manifolds.
.