Help!! Stuck Impeller

[Kevin Henderson]

 
Help!!  I attempted to remove and replace my impeller today from my Oberdorfer raw water pump.  Should be a very easy and routine task.  I opened up the faceplate and removed the snap ring and tried to move the impeller out but it seemed especially sticky.  Remembering that I needed to be cautious about accidentally having the center shaft move out, I held it in place with a screwdriver while trying to slide the impeller off.  No Luck.  The impeller is supple and pliable and all blades are in good shape.  I can slide the old impeller off the shaft about half way but then it sticks.  I pulled and pulled and tried to pry the impeller out but it simply won't move past a certain point.  Has anybody else ever run across such a problem before?  Is there a trick that I'm missing and how easy should the impeller slide out?
I did manage to keep the old impeller in place and stuck a new gasket in.  Ran the engine for awhile and everything is working fine for now.  The clock is ticking and the old impeller has to go. 

Really need the community expertise on this one.

[Kevin Henderson]

I found the following technique in the Moyermarine forum regarding a stuck impeller on an Oberdorfer pump.  It's pretty straight forward except for one step that I thought was controversial  (Highlighted in red)
I had understood that removal of the shaft meant that a person would then have to remove the entire pump and realign the shaft inside.  I think the whole process could be much easier if I could remove the shaft.
I also found another solution that suggested spraying something like PB blaster onto the shaft and impeller... This is really hard on the rubber but could loosen up any salt buildup that can be fusing the bronze insert of the impeller to the shaft.  Would lime away do the same thing?
Again.. any ideas are helpful.

Here's how I do it:

Take off the four screws holding the cover plate on.

Reach in with a pair of needle-nose pliers.

Pull the whole impeller/shaft assembly out.

Take off old snap ring.

Put on new impeller.

Replace snap ring.

Re-insert impeller/shaft assembly.

Replace cover and screws.

Give grease cup a turn or so.

Easy as pie! 

[Stu Jackson]

Kevin, you're right.  Take it all out.  ONLY the really earlier engines had the shaft you couldn't pull out and replace.  I really hesitated to take mine out, but once I did it was a piece of cake.

ANYONE with and engine older than mine, please post and we'll help you out.

[Kevin Henderson]

Stu,
Thank You.  Sometimes the Universal manual is not too clear.  They only have one reference that says the shaft removal applies to early engines, not specifying year or model#.  I also ran across an old post of yours in sailboat owners forum from 2004 talking about the same thing.
So, if I understand correctly on my M25XP engine I CAN remove the center shaft along with the impeller and simply re-insert the ceneter shaft easily while replacing the impeller.

[Stu Jackson]

Kev,

Here's why:

Please read Reply #25, here:  http://c34.org/bbs/index.php/topic,4864.15.html

You might also be interested in reading the entire thread, since it's an earlier version of exactly your topic!

Also, please, please, please, let's not get into another "Sherwood pumps more wtaer than Oberdorfer" discussion.  BOTH pumps work just fine.  My Oberdorfer worked fine with my old 2 inch HX, and even better with the newer 3 inch HX I installed a few years ago.  1986 M25 engine.

Your boat, your choice.  But would I swap for a Sherwood?  No bloody way would I want a pump that I had to remove the faceplate from the back!

[Ralph Masters]

Kevin, Stu and all others,
Have the impe;;er replacement of my pump on the to do list soon, thanks for this post and advice, it will save me head aches in the near future.

Ralph
Ciao Bella

[Kevin Henderson]

I just wanted to post a quick note and update on my Impeller changeout.
Firstly, thank you for clarifying that on my M25XP I do not have to worry about pulling the center shaft out when changing out the impeller.  That was my biggest worry and after finding out I could remove the shaft along with the impeller, the changeout went pretty smooth.
I did however find that the impeller is a real bear to pull off of the shaft and the fit for the new impeller is very tight as well... (Is this normal?)
I ended up "McGyvering" a small wooden dowel to keep the shaft in place while I tapped with a small piece of wood to slip the old impeller off.  I'm definitely going to keep my jury rig handy in the event I need to do a quick changeout.
Really all in all a pretty painless process.
Next week... On to my fuel filters .. YIPPEE

[Ron Hill]

Kevin : I published that the old instructions in the M25XP manual were outdated and applied to an earlier Oberdoffer pump than the M202-15 pump in the M25XP engine.

I wrote that the first time I had to change my impeller (1989?) I took it out (like you with trepidation)!  Then I put it in a vice and took a hammer to it - then I got a bigger hammer!!

The bronze impeller had seized to the stainless shaft - not surprising as that's what 2 dissimilar metals do in salt water!!   

Hopes this helps to explain you plight !!   A few thoughts

[sailaway]

Kevin  I own a 1986 34  Hull #95  M25 engine and my impeller shaft come out. Makes it easy to work on. Charlie