Oberdorfer Impeller kit

[rappareems]

Is there a specific part number for the Oberdorfer impeller kit for the M25 Universal engine.... I think I have a spare but would like a back up.

Mark

[KWKloeber]

#6593

Depending on whether your pump is a:

202 - the cover gasket is #6559
N202 - cover o ring is #9797-034B

Don't buy the impeller kit; you're paying for either an o-ring or a gasket you throw away.

Initially, I always recommend a spare and a Murphy's Law spare.  When you switch out, and buy one new one keep your newest old impeller as the Murphy spare.
Don't install the cir-clip on the shaft; deep six it.
Remove the impeller whilst on the hard to 1) inspect it and 2) keep the fins from getting a "set."
Reinstall with a swipe of SuperLube on the fins/pump case and also the shaft (so the impeller doesn't seize on it.)

-k

[Ron Hill]

Mark : Call DEPCO @ (800) 445-1656 and tell them what you need.  They have the cheapest parts that are reasonably priced!!

A thought

[Stu Jackson]

For 202M-15 pumps:

The impeller kit is #10725.  I just bought one.  This "kit" is for when you want to or need to rebuild your pump, because it includes two seals, an impeller and a faceplate gasket.  You'll still need the pump/engine gasket, but only the engine guys provide that, it is Universal # 298485. Mine cost over $6 CND each, but thst included a stamp for them to mail them to me in a #9 envelope.  I got less expensive ones from my local Kubota tractor dealer using the Kubota tractor parts list in the tech wiki! I bought (4) gaskets, $1.18 ea., Kubota #1529688130.  That gasket for the original tractor engines gasketed the hour meter that was there on farm vehicles, where our pumps are now.  Exact same shape.

EDITORIAL:  Keeping an old impeller to use as a backup is awkward at best, poor maintenance practice at worst.  I highly discourage it.  Buy a gosh-darned new impeller and keep that NEW ONE as the spare.  /Why?  'Cuz puttin' it in should last a LONG time, why bother with something you'll have to do soon again?  You took the old one out for a reason, right?  Plus you waste a gasket if you don't have the N model pumps.  I say this from experience, because my impellers have lasted a looong time, and having to go thru my spares bin to see the one marked "Old" got, well, old.  Now I know for sure that ANY impeller that I find there will be NEW.    And I ewon't have to change an "old backup" out, the new one will last a long time.

[KWKloeber]

Stu, 

Point of information just for accuracy... there's different kits.

10725 is a "minor service kit"; as you say, for replacing the seals on an older 202M pump (does not include the o-ring used on the newer N202 pumps.)

6593K is an "impeller kit" - includes the cover gasket (for 202M) AND the cover o-ring (for N202M) (throw away one of those, so it's cheaper to buy them individually.)

N202M-16MJK is a "major rebuild kit" for N202M pumps (everything except the shaft.)

I agree wholeheartedly w/ your editorial but go one further.
I've had situations where a customer burned up an impeller, thought s/he fixed the problem (or didn't try to troubleshoot it) and then burned up the spare.  That's why I plead with customers to also carry a "murphy's law" spare.  It's an extra expense only on the first purchase of two spares.  With a change out, the newest (or best condition) impeller becomes the "murphy" spare.

Of course, it's TBTC, but it sure comes in handy if one is offshore with a burned up spare impeller.  At least you have a last-chance way to get home.  And the extra insurance is not difficult, keep both in the same container, or zip bag, or wherever, and put a zip-tie thru the hole in the "murphy" spare impeller. 

-k
(Ob dealer)

[Stu Jackson]

>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>

and put a zip-tie thru the hole in the "murphy" spare impeller. 

Ach, for me, I'd be a-wondering what the heck the darned zip-tie was there for.

[KWKloeber]

LOL!! 
Ok, how 'bout one in a baggie, labeled "Murphy" with a Sharpie?

I have CRS so bad that I need to label my left and right hands.

[NewToTheRoad]

Last year I went to change the Impeller for the recently purchased boat.  There was no existing gasket, and I didn't feel that the replacement paper ones fit well (oberdorfer brand kit) so after ripping two of them I decided not to use one. No issues all season.

This year I bought an impeller off Ebay (probably a knockoff) that came with both rubber add paper gaskets.  I was able to get the paper gasket on without tearing it, so I used it.  Fired up the engine, water coming out the exhaust. Next day I motored for 45 minutes then sailed for 3 hours.  When I started the engine to return to the marina, I noticed and odd sound, in following seas, like coughing.  Uh, oh, no water being expelled.  Temp rising to 180. 

Diagnosing, back at the dock it looks like I may have lost the prime.  Tried at the dock, no luck.  Put in the old impeller, threw away the gasket, and voila.

So, my question is, is the gasket really necessary?

Oddly, the replacement impeller seemed to work fine, and initially primed at the dock.  Side by side the knockoff and oberdorfer look pretty identical.  I guess the problem could be the knockoff impeller, or that I used a gasket.  In any event now I'm a bit spooked so will likely order a replacement oberdorfer brand. 

note:  I followed the advice and tossed the snap ring for easier replacement underway if this occurs again.  TBT I was towed in..

[scgunner]

    Lori & Brian,

       When I replace the impeller, which I do at every 100hr service(25 bucks is cheap insurance), before initial start up I remove the screw on top of the pump and squirt WD40 into the hole to lube the impeller before it achieves prime. As soon as the water squirts out of the hole the pump is primed and you can replace the screw. You'll have a bit of water to soak up but the pump maintain prime until the next time you need to change the impeller.

[NewToTheRoad]

Kevin,
  Good tip but I didn't have a problem with the initial prime, after changing.  The problem came after motoring, then sailing the next day.  I found that to be odd, because why did it prime initially, and then lose it?  Maybe the gasket got wet and allowed air to seep in?
Bryan

[KWKloeber]

    Lori & Brian,

       When I replace the impeller, which I do at every 100hr service(25 bucks is cheap insurance), before initial start up I remove the screw on top of the pump and squirt WD40 into the hole to lube the impeller before it achieves prime. As soon as the water squirts out of the hole the pump is primed and you can replace the screw. You'll have a bit of water to soak up but the pump maintain prime until the next time you need to change the impeller.

Kevin

YBYC but it isn't best practice to use a petroleum product on the impeller.  It's better to ease the install of the impeller using a thick slippery lube such as SuperLube gel synthetic grease.  Since Super Lube is a mandated carry-aboard anyway, everyone has a tube handy.  If you want to dribble something into the hole, use mineral oil (baby oil.)  The amount of WD isn't going to be fatal, but just sayin'

-k

[KWKloeber]

is the gasket really necessary?

I guess the problem could be the knockoff impeller, or that I used a gasket. 

Bryan,

No gasket is ever necessary unless the parts being sealed leak!    Some make their own pump gasket from a brown paper grocery bag (does any store still get those ?!?!)

A while back Ob had a problem with a batch of impellers -- they were slightly too narrow and consequently did not seal correctly against the back of the pump body and the back of the cover.  That affected prime, likely not noticeable on the flow rate.

Also, if the back of the cover is worn it will affect prime.  If you have the old style (202M) cast bronze cover it can be refaced.  Or the new flat covers (N202M) can be reversed.

There was an aftermarket cover available that fit the 202M pump body, but had an o-ring to seal against the body.  It also had captive thumb screws.  It's a different size than the N202M pumps/covers and does not fit them.  Don Moyer had 'em, not sure if he still does.  The 202M pumps were used on the Atomic 4, and he developed that cover for customers who still have the old (non N) pumps.

It's always best to use genuine Ob parts, the impeller lists for $41.

-k

[Ron Hill]

Guys : I always put my spare impellers in a ziplock and before closing sprayed the impeller with silicone.  I found that it kept the impeller nimble. 
Did the same with the impeller during winter storage.

A few thoughts

[NewToTheRoad]

Thanks K!

[rappareems]

Thanks to all.... much to ponder.

Mark