M25XPB Water pump replacement – Sherwood vs Oberdorfer

Catalina 36 - M25XPB with Oberdorfer N202M-908
Catalina 36 - M25XPB with Oberdorfer N202M-908

Since day 1 we own the boat, the sherwood water pump was leaking a bit, it was never the top issue but always something bothering me. In this article we are going to go through:

  1. Replacing the water pump
  2. Replacing one of the old cooling hose
  3. Touch up painting of the engine oil crankcase

It took few hours to go through this work, but everything was pretty straight forward.

Original state of Hotel Catalina

Here couple of pictures from June 2016, 2 weeks after we took delivery of Hotel Catalina.

First engine picture June 2016
First engine picture June 2016
First engine picture June 2016
First engine picture June 2016

Based on this pictures we can saw this leak has been there for a while by the rust we can see on the engine.

Time to fix this leak and give some love to the engine!

It has been now over 1 year we own the boat and it’s time to tackle this pump leaking and clean the rust on the engine block.

Here are few of the options to complete this task:

  • get a rebuilt kit and fixing it (tried it, it was worse!)
  • new sherwood pump (very expensive and not so much good feedback on the different forums)
  • migrate (upgrade?) to Oberdorfer
    • Replacing with an Oberdorfer pump that has the base that goes on with the same clip system as your Sherwood pump (more expensive, but more straight forward replacement)
    • If you aren’t scared of, rework the base of the Oberdorfer bolt on pump so it bolts into the pump land on the engine (way cheaper, but a bit too involved in my mind)

After looking online I found a very good deal on the N202M-908 at pump and parts online. Let’s go with this solution!

Oberdorfer N202M-908
Oberdorfer N202M-908

Here is the invoice for the pump:

Replacing the elbow water pump hose

This step is unrelated to the water pump, but it was way easier to complete since the water pump was not in the way anymore.

Old sherwood pump, old hose and old clamp. Everything will be soon replaced.

Tried to clean and fix the sherwood water pump, but the leak was always there.
Tried to clean and fix the sherwood water pump, but the leak was always there.

New hose installed!

Now time to fill the radiator with new coolant! Last time was replaced was last year during the heat exchanger failure.

Now the hose has been replaced, let’s replace the water pump!

The service from https://www.pumpsandpartsonline.com/about-us was very good! Few days after the order I received the part as expected.

I was not sure about the purpose of this hole, and asked online I realized it was to make sure in case of leak of the pump, the raw water has a way to exit somewhere else than in the engine.
I was not sure about the purpose of this hole, and asked online I realized it was to make sure in case of leak of the pump, the raw water has a way to exit somewhere else than in the engine.

Now it’s time for some painting touch up

It’s the first time I try that, I decided to pick white to be able to see if any leak happens in the future. The result is pretty good looking. Next time I have a chance to remove the belt, I will definitely do more painting.

Pump installed and running!

 

 

Temperature is good!

Impeller replacement for my spare kit

https://www.ebay.com/itm/112455220825

Oberdorfer replacement impeller
Oberdorfer replacement impeller

 

Seakamp 200420 zinc replacement

0

Any idea what is the zinc matching the Seakamp 200420 heat exchanger?

Seakamp just replied to me ​”¼  npt thread zinc is 1.7 inch”

Checking on the catalina36.org association, I got recommended size E0 from this site.

They also have a page for the kind you screw into the brass cap – but you may have to cut that to length.

Anyway I had to cut to the length even the E0, as soon as it was inserted the water was not able to go through anymore.

 

AC circuit corroded bus bar replacement

0

One of the item to tackle from our purchase survey! The original bus bar for the AC circuit was corroded. It was a straight forward maintenance.

Less of $20 bus bar from blue sea and some jumpers.

Cabin teak floor varnishing

0

The 2 cabin boards near the engine came with the boat in a pretty bad shape, they were in need of some love. I decided the risk was very low to exercise my varnishing skills on these boards. The result happened to be way better than I expected.

Update March 2019. After this rainy winter and couple of leaks, it’s time to do the forward cabin floor board.

Tools & Chemicals

Preparation

  • Pour the stripper on to the wood in a puddle
  • Spread it initially with a brush
  • Allow the stripper to “work” for 10-15 minutes
  • Start to scrape with a 3″ flat putty knife
  • Pile up the stripper/old varnish in the middle of the board
  • Use a couple larger putty knives to remove the stripper/old Varnish
  • Dispose of it in a shoebox with a plastic bag liner.
  • Repeat the entire process anywhere from 3 to 5 more times.
  • Once all or most of the varnish was removed clean the wood with acetone
  • Allow to dry overnight and clean the wood with acetone again
  • After completely drying lightly sand the wood with 220 grit paper
  • Wipe it down with acetone again
  • At this point it is ready for epoxy / varnish

Update March 2019. I replaced CitriStrip with Klean Strip for the forward board, way easier to apply.

Epoxy / Varnishing

Start with 4 coats of clear coat of epoxy. I usually apply the 4 coats of epoxy in less of 48 hours.

Continue with 4 coats of undiluted Epifanes Varnish.

Update March 2019. 2 years later the Epifanes Varnish was still ok, but added a bit of mineral spirit before to apply it.

Galley and Head LED lights update

After couple of fluorescent tube decided to stop working, we decided to upgrade the couple fixture with modern looking one.

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