IMPELLER BLADE ANGLE

larglo · Post by **larglo** » Sat Feb 12, 2011 12:03 pm

Hi all,

With the coming higher temps on the way, I will have more questions coming about the F25, and here is one of them.

Last fall, I had an overheat problem and found out the impeller was messed up in the raw water pump. I removed the pump, and winterized the engine. Got a new impeller and I will be installing the new impeller into the pump housing soon, but was wondering which way I should curve the blades of the impeller when placing it into the housing?
I guess it depends on rotation?
Could it also be, not to make a difference, because they will flip to the correct curve, angle, or what ever, when the engine first starts? And, is there anything I should know or do when installing the impeller?

Any thoughts and advise will be helpful.

Thanks,

Larry

prowlersfish · Post by **prowlersfish** » Sat Feb 12, 2011 12:17 pm

Put in the impeller ether way and then turn over the engine then vanes will be facing the right way .

Big D · Post by **Big D** » Sat Feb 12, 2011 6:13 pm

Larry, like Paul said, it'll flip. I also like using dish soap to coat the blades when installing. Makes it a little easier to install and lubricates on a dry start up.

Big D · Post by **Big D** » Sat Feb 12, 2011 6:27 pm

Larry, if I remember correctly, you have a Merc right? Those pumps can be a little tricky. Make careful note of the position of the pump body when you take the halves apart. They are stamped next to the hose attachment points for LH out and RH out. This reffers to engine rotation. Make sure you reassemble the bodies the same way, and that the incoming supply hose goes to the correct port on the pump or you'll be pushing water instead of pulling from the lake. There are pics of these pumps in previous posts that would help. Do a search or perhaps those that posted will do so again.

captainmaniac · Post by **captainmaniac** » Sat Feb 12, 2011 6:30 pm

Do you guys tend to pull your pumps to swap impellers, or do 'em in place?

Big D · Post by **Big D** » Sat Feb 12, 2011 6:44 pm

Captain, really depends on the application. Even when designed by the engine manufacturer to be replaced without removing the pump, the boat's design can make it impossible to replace the impeller without removing the pump first.

prowlersfish · Post by **prowlersfish** » Sat Feb 12, 2011 7:01 pm

On my port engine I pull the pump , the starboard I do it on the engine .

alexander38 · Post by **alexander38** » Sat Feb 12, 2011 7:20 pm

On my merc's pull both. And change parts off boat

Big D · Post by **Big D** » Sat Feb 12, 2011 7:46 pm

Up against the stringers Tony?

larglo · Post by **larglo** » Sat Feb 12, 2011 7:51 pm

BigD, all

Nope, gotta, Chrysler 318. Thanks guys for the help. First warm day in long while, so had to go to the boat. Got the rail anchor mount adjusted to hold anchor, but have to come up with a bumper to keep anchor from bouncing into the rub rail while underway. I do think I'll like using anchor from the stern.
I bet it was 10 to 15 degrees colder under the dock roof, so could only stay a shot time, but will try again Sunday.

Thanks again,

Larry

Big D · Post by **Big D** » Sat Feb 12, 2011 7:56 pm

Sorry Larry. For some reason I thought the tranny oil cooler post was yours, I remember a black engine.....my bad!! Mine are blue too!

rbcool · Post by **rbcool** » Sat Feb 12, 2011 10:27 pm

I'd say the PCM pump impeller is the easiest gasser to change, on engine. But I like to remove the pump to change customers impellers. Forces you to check numerous things ; condition of hose ends, belt, new clamps, tightening of all belts.
And I like to use some Dawn upon reinstalling the impeller, but not much need to worry about rotation of impeller, it'll immediately set itself right.
Like Tony said, the merc pump is always something I work on while sitting on the dock.

Ron

alexander38 · Post by **alexander38** » Sat Feb 12, 2011 10:56 pm

Yes the port right next to the stringer and the stbd one I'd have to hang up side down to see it and there's only 3" of hose go from the discharge to the oil cooler.
And Larry make sure you get that sucker in right or she'll not suck but blow and tear up those new blades. And I lube mine with lard, its a Navy thing.

prowlersfish · Post by **prowlersfish** » Sat Feb 12, 2011 11:57 pm

Tony , you mean put the pump back on the right way ? correct ?

alexander38 · Post by **alexander38** » Sun Feb 13, 2011 6:03 am

Yes the pump is what I'm talkin about, like an earlier post warned about it has a left and right rotation one way it sucks andther other it blows.

and Larry check your risers make sure they don't get hot and the pumps working,
Have you taken the old one apart ? How worn is the end plate ? And the shaft ?