2 lbs water pressure at idle ok ?

[StratMan290FS]

Hey i have a 1990 Evinrude 175 XP, and i have been wondering if the water pump/impeller is alright, i get about 2 or so lbs pressure while at idle and low rpm, once planed out around 3000 rpm and more it varies between 10 and 15 lbs of pressure, just wondering if this is normal or not ?

 

[Solittle]

Re: 2 lbs water pressure at idle ok ?

The value of a water pressure gage in my book is not what it reads at a point in time but how the reading changes over when you last replaced the water pump. If your reading at speed with a new pump is 20 lbs and two years later it is reading 15 it is telling you that you need at a minimum a new impeller.<br /><br />When did you last replace your water pump? I run 1.6L V4s and get about 5 lbs at idle and around 20 at speed.

 

[StratMan290FS]

Re: 2 lbs water pressure at idle ok ?

Just recent bought the boat last year, and it was running the same pressures i believe, but probably only have 5-10 hours on it, everyone else i talk to is running 4 or more... hmm....

 

[emdsapmgr]

Re: 2 lbs water pressure at idle ok ?

A new pump will idle at 6-9 lbs and can go as high as 22 lbs at full speed. 10 lbs is the absolute minimum at high speed. Sounds like you are due for a new impeller.

 

[woodduck17]

Re: 2 lbs water pressure at idle ok ?

So, just how accurate are the dash mounted pressure gauges? Seems like you have a good difference between idle and WOT.

 

[billaranguren@yahoo.com]

Re: 2 lbs water pressure at idle ok ?

Where can I get a water pressure guage to measure mine? Where does it hook up? I have a 1999 Johnson 200 HP. Sure beats replacing it on a guess.

 

[rickdb1boat]

Re: 2 lbs water pressure at idle ok ?

Woodduck<br /><br />It's not so much the accuracy of the gauge as it is the consistency of the readings. As SoLittle said, it how the readings change over time that counts. There should be a good difference between idle and full throttle. As engine speed increases, so does the speed of the pump and therefore you get the higher readings and more cooling pressure at higher revs when it's needed most. Guages are available at the dealer and online (I believe iboats has them). They "T" into the tattletale hose in most cases...

 

[muchco]

Re: 2 lbs water pressure at idle ok ?

SORRY in advance for high jacking the thread. While your on the water pump and pressure topic I have a few quick question regarding replacement water pumps. I have read on previous posts the mention of high pressure and/or high volume water pumps. Is there such a thing? When I look for a replacement for my 1987 V6 150XP I can only find one part #5001594. I had just replaced my water pump and I have 6 psi at idle 12-14 psi at 3500 and 16-18 psi WOT. I have heard and read that 10 psi is a minimum WOT pressure and some that use high pressure pumps (if there is such a thing) get upwards of 25 psi pressure. I have just purchased a digital laser temprature reader and I intend to check my head temprature at idle and WOT throttle.<br />I beleive that the thermostats are 143 degrees. Is this the head temprature I should get at idle and WOT?

 

[StratMan290FS]

Re: 2 lbs water pressure at idle ok ?

So it sounds to me like i need a new water pump since im only getting 2 at idle and 14-15 max at WOT, i guess this would be the best security since i plan to keep the boat for awhile.

 

[Solittle]

Re: 2 lbs water pressure at idle ok ?

mucho - You have some good questions but start a new thread with them.