Trying to identify Oberdorfer raw water pump

[robertr0816]

Hey anybody know which pump this is.
Trying to rebuild this Oberdorfer(I think) pump on my  M25xp engine.

[Noah]

Should be a N202M-16. (1/2 in.) I just went through this with mine. If you rebuild it yourself it will be cheaper. I had mine rebuilt by a shop and it ended up just marginally cheaper than buying a new one. A new one online cost $370 with free shipping.

[Jon W]

Oberdoerfer N202M either-15 (3/8"npt inlet and outlet), or -16 (1/2" npt inlet and outlet).

[robertr0816]

Thank you.
Found a repair kit on ebay for 89bucks. Not too bad.

[Stu Jackson]

If you haven't seen this, the guts should be the same, good luck.

Oberdorfer Pump Rebuild 101 - http://c34.org/bbs/index.php/topic,6766.0.html [Link added to main page of C34 Tech wiki]

[KWKloeber]

Based on the year of the boat (unless she was repowered or the pump replaced) it is a 202M pump not an N202M pump

The number on the body does not match the casting for an N202M pump, but back then (before the company was sold 3 times) Ob had a casting number not part number on the body.   Current N202M pumps carry the part number and date code on the body.

Make sure it is a GENUINE Oberdorfer kit and includes the cover gasket (not o-ring.)

Inspect the shaft for scoring or wear at the location of the lip seals, and the fit of the shaft in the carbon bearing before you order the parts you need.

Note that there is a cover available if you want to mod an old 202M pump to use an o-ring rather than the paper gasket.

[robertr0816]

When took the cover off this pump had the O ring on the body not the cover.

Based on the year of the boat (unless she was repowered or the pump replaced) it is a 202M pump not an N202M pump

The number on the body does not match the casting for an N202M pump, but back then (before the company was sold 3 times) Ob had a casting number not part number on the body.   Current N202M pumps carry the part number and date code on the body.

Make sure it is a GENUINE Oberdorfer kit and includes the cover gasket (not o-ring.)

Inspect the shaft for scoring or wear at the location of the lip seals, and the fit of the shaft in the carbon bearing before you order the parts you need.

Note that there is a cover available if you want to mod an old 202M pump to use an o-ring rather than the paper gasket.

[KWKloeber]

I When took the cover off this pump had the O ring on the body not the cover.

[there is a cover available if you want to mod an old 202M pump to use an o-ring rather than the paper gasket.

Very interesting. The info I have shows the N pumps were introduced after 1988.  I replaced my old Ob pump several years after that and the replacement was a 202M-15, not an N202M-15!  correction - mea culpa; the 202M-07 that was OEM was replaced with an N202M -15. 

The cover that mods the old pumps has the O-ring in the cover.

[Jon W]

Isn't the N202M the replacement for the 202M? Any idea what's different between them? Thanks for the help.

[KWKloeber]

Jon

Yes.

The N upgrade changed from a paper gasket to the o-ring, which necessitated redesigning the body wider to add the O-ring groove.  The 202M had a replaceable cam, while the cam is now cast into the body of the N202M.

My point about the 202M was that literature I have from Ob indicates that the N pumps were introduced after 1998.   But maybe that is in error. 

[Jon W]

Thanks, somewhere along the line mine was changed to an N202m-15. Would make more sense to install a  -16 since the hoses are 5/8", but it works.

[Ron Hill]

robert : When you replace the "lip seals" you need to inspect the stainless shaft  - to make sure that it is not worn!!

A thought

[KWKloeber]

Thanks, somewhere along the line mine was changed to an N202m-15. Would make more sense to install a  -16 since the hoses are 5/8", but it works.

Jon

Are you sure it was changed to -15?
It's possible that was what was originally installed.

[Jon W]

Ken, I'm not sure. I found this behind the port salon cushion shortly after buying the boat. Could have been something a PO picked up as a spare, but I thought it was the original. Now that I dug it out I might as well refurb it.

[KWKloeber]

Is that 1/2" or 3/8"?