What's a good water pump reading?

[Mac3]

Hi all,
I've owned my 98 Johnson 150 ficht for 2 years now, done around 100 hours but I still consider myself a know nothing newbie. It has performed faultlessly until recently when I had the check engine and water temp warnings come up. This was good because it shook me out of complacency to learn more about the thing that hangs off the end of my boat. I replaced the impellor and I'm sure the engine warning was due to the fact that I emptied the out of date auxiliary 2 stroke fuel in the main tank. I have since replaced the fuel filters as well. I went for a test run today, all good, but the the water pump gauge was flicking all over the place, previously at cruise speed it sat on about 9 oclock. I'm thinking there is some blockage in the water area but the tell tale was drilling a hole in the sea, should I worry about it?
David

 

[Chris1956]

Re: What's a good water pump reading?

Dave, I have a '98 150HP V6, which is pretty similar to your motor. I replaced the impeller this year and get 30+ PSI at WOT. I get in the 20's ar cruise speed.

 

[Vic.S]

Re: What's a good water pump reading?

What's a good water pump reading?

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[Mac3]

Re: What's a good water pump reading?

I guess all the answers are in the manual. I thought the idea of forums was to share opinions and observations. I'll rephrase the question- is a high reading as I had wrong and now the 20-30 ok? Looks like Chris has answered that already.
David

 

[Vic.S]

Re: What's a good water pump reading?

The important thing surely is to compare the pressure readings you observe with what the manufacturers of the engine quote as the correct pressures. If they don't give figures then you compare what you observe now with what you saw when you knew everything was in good working order.

If the pressure rises then it is either due to blockages in the cooling system after the point to which the gauge is connected or to the pressure control device failing to open and control the pressure.

If the pressure falls then it could be due to an obstruction of the water intakes, wear in the water pump, obstruction of the cooling system before the gauge connection or again due to the failure of the pressure control device to correctly control the pressure.

It should be obvious from that that a combination of a fault from the last paragraph combined with a fault from the previous one could conspire to give you a normal reading and so lull you into a false sense of security and the belief that all is well when it is not, but a change in reading from specification or normal should alert you to the fact that something is wrong.

 

[Mac3]

Re: What's a good water pump reading?

Copy all Vic, this is more like the stuff I like about forums.
David