Clark Pump Leaking

[Dreaming Yachtsman]

BACKGROUND:
This morning I discovered 6 inches of water in my normally dry bilge. I also noticed a few drops of water near the Spectra Catalina 300 watermaker so I suspected it as the source of the leakage. When I started the unit, water began oozing from the joints between the Clark pump center block and both cylinder end caps (Pump serial number is 2969-10). I shut the system down and tightened the 4 large set screws 1/8 to 1/6 turn each. The leakage was down to a slow weep when I test ran the system again.

QUESTIONS:
1. How common is leakage from this location?
2. Is there anything I can do, short of pump dissassembly and overhaul, that might completely stop the leaks?
3. What is the specified torque for the setscrews?
4. Why would the joints start leaking now?
5. Anyone else ever had this problem? If so, how did you fix it?

[belizesailor]

Yes, I have a Catalina 300, and I had a similar leak in my clark pump a couple of years ago. Spectra sent me replacement parts at no charge. Their tech support is great. And, there is a detailed document specifically for repairing the clark pump. I think it is posted on their web site, but if not PM me your email address and I can send it to you.

The entire system is quite easy to work on. No special tools required. Lots of small parts, but parts diagrams and support are good, some digital pics taken during disassembly are a good idea too.

Sounds like you just need to replace some seals. Easy job.

My suggestion, call Spectra and describe your problem they will recommend parts. Also, you may want to consider applying some of their engineering revisions while you're in there -- they can tell you which are applicable to your unit.

[Dreaming Yachtsman]

BelizeSailor,
The repair procedure on the Spectra web site says the J tubes must be replaced. How expensive does this repair become, assuming a few upgrades along the way?

[belizesailor]

In my case, my repair cost me nada. Spectra sent the parts at no cost. I did the repairs myself. The only thing I replaced was a few seals and one end block with a small crack in it.

Not sure of the exact costs of the engineering changes, but prices are available from Spectra. As I recall, many of the engineering changes just involve changes in materials (same basic parts -- different stuff).

Spectra will of course do all of this for you if you choose, including apply the most recent upgrades, but you have to send the unit into them. I think fees for for a factory rebuild/update are published on their web site, or at least available from Spectra.

[Tellie]

Originally Posted by Dreaming Yachtsman

BACKGROUND:
This morning I discovered 6 inches of water in my normally dry bilge. I also noticed a few drops of water near the Spectra Catalina 300 watermaker so I suspected it as the source of the leakage. When I started the unit, water began oozing from the joints between the Clark pump center block and both cylinder end caps (Pump serial number is 2969-10). I shut the system down and tightened the 4 large set screws 1/8 to 1/6 turn each. The leakage was down to a slow weep when I test ran the system again.

QUESTIONS:
1. How common is leakage from this location?
2. Is there anything I can do, short of pump dissassembly and overhaul, that might completely stop the leaks?
3. What is the specified torque for the setscrews?
4. Why would the joints start leaking now?
5. Anyone else ever had this problem? If so, how did you fix it?

Hi DY,

Just to clarify, you're describing three areas of leaking. 1) the center block 2) both ends of the Clark pumps end caps.

For a Clark pump to suddenly develop three leaks and especially in the three areas you describe is very, very, unusual and a sign that something else other than normal wear and tear are at fault. Did you attempt to tighten down the SS fittings on the end caps? Again it's very, very, unusuall for both end caps to leak at the same time. The leaking area betwen the Clark pump center block would usually indicate an O-ring has failed, a simple repair. The one thing you do not want to do is tighten down any fitting or bolts to stop a leaking Clark pump or serious damage can result. Is it possible for you to take a picture of the three leaking areas and post them? If I can see it I can tell you how to best fix it.

[Dreaming Yachtsman]

Tellie,

Thanks for the answer about torquing the setscrews. Hopefully I have not done too much damage by tightening them as much as I did.

Apparently my choice of terminology was incorrect when I said leakage "between the Clark pump center block and both cylinder end caps". The reference to "end caps" was to the square end of the cylinders that bolt to the center block, not the round caps on the ends. I could not find any other term for those square pieces in the Spectra maintenance bulletin. Thus, I do NOT have 3 simultaneous leaks, just two (both seams on the center block).

I tried taking a picture but the lighting wasn't good enough for my cell phone camera to see anything.

Thanks for the quick response.

[Dreaming Yachtsman]

Tellie asked for a picture. I can't get one of the actual leaks so I downloaded a picture from Spectra.com, cropped out the unwanted parts, and annotated the locations of the leaks. Hopefully it will clarify the issue.

Ok, the red X indicates something is wrong with the link to the picture I just uploaded to my CF photo album.
Let's try attaching the file.

[Tellie]

Originally Posted by Dreaming Yachtsman

Tellie asked for a picture. I can't get one of the actual leaks so I downloaded a picture from Spectra.com, cropped out the unwanted parts, and annotated the locations of the leaks. Hopefully it will clarify the issue.

Ok, the red X indicates something is wrong with the link to the picture I just uploaded to my CF photo album.
Let's try attaching the file.
Attachment 38152

Unless there is something not shown it is a simple repair. Two new O-rings on each side and it's fixed.

[Dreaming Yachtsman]

Many thanks to Tellie for his assistance and moral support during this episode. He diagnosed the problem exactly (failed O-rings on check valves), referred me to a local parts supplier, and talked me through the disassembly by telephone.

As belizesailor noted in his post, the repair was quite simple, especially so with Tellie's expert guidance. The hardest part of the job was getting the baseplate hold down screws back onto their holes.

Test ran the system this afternoon for about 5 minutes with not a drop of leakage, even from the HP compression fittings I disconnected to remove the pump from the engine room. Didn't run it longer as the boat is sitting in a marina with who knows what chemicals in the water. Plan to run it again for at least 1 hour when I get to clean water again in a few days.

[belizesailor]

Originally Posted by Dreaming Yachtsman

Many thanks to Tellie for his assistance and moral support during this episode. He diagnosed the problem exactly (failed O-rings on check valves), referred me to a local parts supplier, and talked me through the disassembly by telephone.

As belizesailor noted in his post, the repair was quite simple, especially so with Tellie's expert guidance. The hardest part of the job was getting the baseplate hold down screws back onto their holes.

Test ran the system this afternoon for about 5 minutes with not a drop of leakage, even from the HP compression fittings I disconnected to remove the pump from the engine room. Didn't run it longer as the boat is sitting in a marina with who knows what chemicals in the water. Plan to run it again for at least 1 hour when I get to clean water again in a few days.

Hoorah!