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Water Pump Replacement or Retrofit, 1/2" Oberdorfer

<span style= >Water Pump Replacement or Retrofit, 1/2" Oberdorfer</span>

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Water Pump Replacement or Retrofit, 1/2" Oberdorfer

Part #: Z2880

$450.80

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Description
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More Info
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Warnings
& Notes
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FAQ’s

New raw water pump for your 5411, M-12, M-2-12, M-18, M-25, or M-25XP Universal Diesel engine. This Oberdorfer #N202M16 pump is a direct replacement for most Oberdorfer or Sherwood water pumps on these M series engines engines. For 5424, M-30, and M-35 engines, see additional information in the "More Info" tab.

Includes mounting gasket.

There are several improvements compared to earlier pumps:
• The new pump has sealed bearings which eliminate the old grease cup featured on the early pump designs for easier maintenance.
• An "O" ring seal on the removable back plate eliminates the old gasket that needed to be replaced every time you change the impeller.
• Output is equal to pumps used on the newest of the above engine models and greater than on earlier models.
• 9-1/2 gallons per minute at 2500 RPM and zero head
• 6-1/4 GPM at 1750 RPM and 10' head

If your engine uses an adapter plate between the engine block and the pump, simply remove that adapter plate before installing this pump.

You are likely aware that the old Universal engine company used several different pumps throughout the production of each of these engines. Functionally, all of these pumps were equivalent. Universal probably used different vendors to ensure an uninterrupted supply of pumps. It is also likely that, by using two vendors, they were able to negotiate better pricing by encouraging the vendors to bid against each other. We selected this Oberdorfer pump as it currently offers you a savings of more than $150.00 when compared to a Sherwood pump, and will give you the same long life and quality service.

Some owners have chosen to replace their Sherwood water pump with this Oberdorfer pump both because the Oberdorfer is less expensive, and because replacing the impeller on an Oberdorfer is much easier than on a Sherwood. Some modifications will be required if you are replacing a Sherwood with an Oberdorfer on an Universal 5424 / M-30 as well as an M-35 A or B. Please click this link to an article on the Catalina 34 National Association web site for extensive additional information. Decide if you are willing to do the required modifications yourself before ordering. If you would rather not have to modify the pump, see our replacement, machined pump, part Z3936, below in "May we also suggest."

1) This pump is equipped with 1/2" National Pipe Thread (NPT) ports. Remember, a pipe thread is tapered and a 1/2" thread doesn't measure 1/2" anywhere... See the tech support article below titled "Pipe Sizes and Why They Are So Confusing for more information.

2) The drive shaft of the pump has a male connection to the engine (see "More Images" below). If you require a female connection on the pump shaft, please call Catalina Direct tech support at 916/843-1971 for additional assistance.

3) A very few owners of early Universal 5411 raw water cooled engines report that their engine was equipped with an aftermarket fresh water cooling system. This system had a second Sherwood pump that was different than the raw water pump. The Oberdorfer pump above will not replace the fresh water pump used on this aftermarket kit. There is no known replacement.

4) Universal’s newer "B" series engines are more powerful than earlier models. The M-35B has 20% more power than the M-35 and 56% more power than the M-25XP that it replaced. More power equals more waste heat. Late Sherwood pumps move more water than Oberdorfer pumps. That said, we have had many customers successfully retrofit Oberdorfer pumps even on "B" series engines without any issues. That makes it hard to know if the higher capacity is necessary or overkill.

If you have a smaller engine and sail in northern latitudes with colder water, you are likely to have more acceptable results with an Oberdorfer pump than if you are in warmer waters with a large engine. Keep a close eye on engine temperature after any retrofit to ensure that the new pump is up to the task. If yours is an M-35B engine, you have the most waste heat to reject and the greatest chance of overheating in adverse conditions.

Retrofitting an Oberdorfer pump to an engine that came standard with a Sherwood is always at your own risk. If you decide to try the retrofit and find the performance unacceptable, your only recourse is to purchase another Sherwood pump. Once used, you may not return the Oberdorfer pump for performance reasons.

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Will an Oberdorfer pump fit in place of my original Sherwood pump?

Yes, an Oberdorfer pump will physically mount in replacement of a late model Sherwood pump but that does not mean it will provide adequate cooling.
Does the Oberdorfer or Sherwood pump have greater capacity?

The Sherwood will pump more water with more vanes on a larger impeller.
Which pump do you recommend for my engine?

We suggest you follow the engine manufacturer’s recommendation.
Have other customers replaced their Sherwood pump with an Oberdorfer?

Yes. Many M-25, and M-25XP owners report successful replacement. When asked “Have you simulated clawing off a lee shore by running at full throttle in heavy winds for an hour to test for overheating?” the answer is always “No”.
Have owners of M-35 and M-35B engines replaced their Sherwood pump with an Oberdorfer?

Yes, but a few customers report the engine begins to overheat when pushed closer to the boat’s hull speed and will continue to get hotter with a longer run. Returning to the Sherwood pump resolves the overheating.
Does a new pump come with an impeller and mounting gasket?

Yes, we include both when you purchase the kit from Catalina Direct.
I’m not sure which pump I have. How do I tell?

See the Tech Support articles below “Identifying the raw water pump on Universal engines” and “Raw Water Pump Replacement for 5411, 5424, & M-30 Engines”
Are there any other parts I may need?

If you replace a Sherwood with 1/2” ports with an Oberdorfer with 1/2” ports, the ports are closer together on an Oberdorfer. You must replace the large 1/2” inlet elbow with one offered offered below under “May we also suggest” #Z3955 to avoid having them interrfere with each other.

You should also consider having a spare impeller as well as a pair of Water Pump Snap Ring Pliers offered below under "May we also suggest"

1
Show
Description
2
Show
More Info
3
Warnings
& Notes
4
Show
FAQ’s

Will an Oberdorfer pump fit in place of my original Sherwood pump?

Yes, an Oberdorfer pump will physically mount in replacement of a late model Sherwood pump but that does not mean it will provide adequate cooling.
Does the Oberdorfer or Sherwood pump have greater capacity?

The Sherwood will pump more water with more vanes on a larger impeller.
Which pump do you recommend for my engine?

We suggest you follow the engine manufacturer’s recommendation.
Have other customers replaced their Sherwood pump with an Oberdorfer?

Yes. Many M-25, and M-25XP owners report successful replacement. When asked “Have you simulated clawing off a lee shore by running at full throttle in heavy winds for an hour to test for overheating?” the answer is always “No”.
Have owners of M-35 and M-35B engines replaced their Sherwood pump with an Oberdorfer?

Yes, but a few customers report the engine begins to overheat when pushed closer to the boat’s hull speed and will continue to get hotter with a longer run. Returning to the Sherwood pump resolves the overheating.
Does a new pump come with an impeller and mounting gasket?

Yes, we include both when you purchase the kit from Catalina Direct.
I’m not sure which pump I have. How do I tell?

See the Tech Support articles below “Identifying the raw water pump on Universal engines” and “Raw Water Pump Replacement for 5411, 5424, & M-30 Engines”
Are there any other parts I may need?

If you replace a Sherwood with 1/2” ports with an Oberdorfer with 1/2” ports, the ports are closer together on an Oberdorfer. You must replace the large 1/2” inlet elbow with one offered offered below under “May we also suggest” #Z3955 to avoid having them interrfere with each other.

You should also consider having a spare impeller as well as a pair of Water Pump Snap Ring Pliers offered below under "May we also suggest"