Impeller Install

[KeelsonGraham]

Sorry, dumb newbie question.

Does it matter which way you bend the impeller blades when reinstalling? Will they take up the correct bend as soon as you run the engine without damaging themselves? Or is it critical to bend them in the correct orientation when fitting?

[waughoo]

It will set itself in the correct LEAN after one rotation.  Make sure to use some sort of lubricant when installing the new impellor to aid in this activity.  I use dish soap as it is onboard. 

[scgunner]

Graham,

I also do a prelube like Alex then I remove the bleed screw and start the motor as soon as you get water through the hole replace the screw this removes the air from the system and minimizes the amount of time the impeller spins without water.

[KWKloeber]

Put a schmear of SuperLube ptfe gel to help prevent the imp from binding onto the momma shaft.**
A schmear on the case and cover/o-ring is a good prelube.
Of course, deep six the cir clip and washer!!

Tightening a zip tie around the imp is a way to make it easier to insert.

** If the imp won't let go of the shaft when you change it out,
     + pull out the shaft.
     + grab a box wrench that the shaft will slip thru and the imp hub sits against. Or a Crescent(tm) wrench works in a pinch.
     + overhang the end over a firm surface (like a timber or conc wall).
     + tap the shaft out of the imp hub using a bolt against the shaft.

SuperLube the end of the shaft and carefully/gently insert it with a twisting motion to avoid nicking the two rubber lip seals.  AFTER it's seated onto fork on the cam shaft THEN install the new imp.

[Ron Hill]

Keel : Like Ken said, wrap a zip tie around the impeller to compress it.  To "lube" it I use dish washing soap so there is NO residue in any of the hoses or muffler. Then just start the engine and the blades will fix themselves and the soap will take care of the dry cavity until raw water is pumping!!

A thought

[KeelsonGraham]

Brilliant, Thank you all!

[Stu Jackson]

If you haven't yet, don't bother with the zip ties.  I just hold the impeller on the shaft in front of the pump and twist it while pushing gently.  it goes right in.  Then I keep twisting to get the inside end of the shaft set properly and then impeller vanes then go all the way in.

[KWKloeber]

If you haven't yet, don't bother with the zip ties.  I just hold the impeller on the shaft in front of the pump and twist it while pushing gently.  it goes right in.  Then I keep twisting to get the inside end of the shaft set properly and then impeller vanes then go all the way in.

Stu

Are you removing the shaft to change the impeller, or just "unseating it" from the camshaft?

[Stu Jackson]

Ken,

Doesn't matter, but I don't recall ever taking the impeller off without pulling the shaft, and no, I don't use the circlips any more.

[KWKloeber]

Stu

It absolutely matters whether it's a slight pull back or a full removal. 
In that it's playing with fire to fully remove the shaft. There's the chance (albeit slight) of nicking the lip seal when teplacing it, and unless the impeller is seized on the shaft, there's (IMO) no reason to pull it. I always hold the shaft with a screwdriver or something blunt and pull the impeller w/ a needle nose.
Just "my pump, my choice/caution" I suppose.

That's the simplicity of "approaching" (ugggh) the pump w/ the impeller zip tied - the impeller mates on the flat, no twisting of a (necessary loose) shaft is needed.

[Stu Jackson]

Ken, I've rebuilt my pump a few times, and venture to offer that those lip seals are pretty hefty, and agree that care should be taken when reinstalling the shaft in any and all times.

"...playing with fire to fully remove the shaft..." - hardly.

[KWKloeber]

Ken, I've rebuilt my pump a few times, and venture to offer that those lip seals are pretty hefty, and agree that care should be taken when reinstalling the shaft in any and all times.

"...playing with fire to fully remove the shaft..." - hardly.

OK, I'll clarify.  My point (not well articulated) is that I, too, oftentimes do things that I would never tell the "average" boater to undertale (say, fiddling around the starter with a screwdriver to short the "S" terminal to the "B" terminal.)  I take the course that those things are best left unsaid unless one knows the others' abilities and the level of care inherent to them.

Although I sometimes do, I'd never suggest that removing the pump shaft is a good idea for the masses to undertake whenever they charge an impeller. 

Their boat, their choice, of course, but I would never myself suggest that, for the unaware, they undertake something that could be playing with matches -- when in the first place it is totally unnecessary to even get out the matchbook.
   

[Ron Hill]

Stu : Keel has a M35B engine with a Sherwood pump.  It is much easier to take a zip tie around the blade to compress them for installation.  You have a Oberdoffer which your way works.  I've done impeller changes both ways (Shrwood & Obdfr) and the zip tie works best with the Sherwood!

Like Ken said - I've started a M25XP engine by taking a wooden handle screwdriver and going with the shank across the starter solenoid terminal to the engine block, but I wouldn't recommend it to most people!!

A few thoughts 

[KWKloeber]

https://c34.org/bbs/index.php/topic,11467.msg92521.html#msg92521

Then we wouldn't need to rely on Ron to tell us!!

[Ron Hill]

Ken : You are right again!!  There are all kind of plumbing hard pipe & hose adapters out there!!  Don't need me to say that.

A thought