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Johnson raw water pump: leaking seal

Jun 25, 2004
282
Hunter 306 Pasadena MD
So this is more of an informational / sparking conversation posting, as I don't really think I have a question.

I have a Johnson 10-24509-01 raw water pump (or F4B-903: not sure which is the real part number) on my Yanmar 2GM20F engine from 2004. Around a month ago, I noticed a small puddle of seawater under the pump (maybe 3" diameter) after running for a few hours. First leak in 16 years. By last weekend, that had grown to more like 1/2 cup of water (a very large puddle) over a 3.5 hour run, and I could see maybe 1 drop every 1-2 seconds coming off the pump. Figured it was probably the seal around the shaft.

So I followed the instructions kindly posted by Ken13559 in 3GM30F Raw Water Pump , and took it all apart. When I got the lip seal out, I thought the problem was pretty obvious. Check it out (after and before removal, and different sides):
seal_out_of_pump.jpeg seal_in_pump.jpeg

It looks like the spring (that I assume is in there around the inner rubber ring) has rusted so badly that it has pushed right through the rubber on the back side (non-impeller side) of the seal. Anyway, it seems to be a GACO part with a part number which says DPSM 12247. Ken13559 , in his writeup, had it as "Oil Seal p/n: 12x24x7-TC-NOK", which I couldn't find anywhere online. I ended up calling Depco (Depco Pump Company). They didn't want the seal part number: just the F4B pump number. The guy said "you probably couldn't find it because we have all of them here...". Haha. Anyway, I ordered just the seal from Depco for around $10 (including shipping, I hope), vs. some $55 for a kit off of eBay which contained lots of parts I don't need. (The bearings look and feel fine.)
 
Aug 1, 2011
3,957
Catalina 270 255 Wabamun. Welcome to the marina
This is the problem with older equipment. We see it all the time in the network world, the version changes and once the production over run stock gets depleted, there's little to no repair stock. If you order two of the seals from Depco, you'll never have a problem, (and likely lose the one you have) and if you order one, that one will fail just after they sell the last one they have.
 
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Likes: ggrizzard
Jun 25, 2004
282
Hunter 306 Pasadena MD
This is the problem with older equipment. We see it all the time in the network world, the version changes and once the production over run stock gets depleted, there's little to no repair stock. If you order two of the seals from Depco, you'll never have a problem, (and likely lose the one you have) and if you order one, that one will fail just after they sell the last one they have.
Yeah: I thought about ordering a second seal about 5 minutes after getting off the phone. Geez...
 
Aug 1, 2011
3,957
Catalina 270 255 Wabamun. Welcome to the marina
Yeah, and another $10 to ship it. Theres a pattern here and Besos is the only one getting rich from it :)
 
Oct 29, 2005
2,182
Hunter Marine 326 303 Singapore
Jaysweet, any single or double lip seal with size 12x24x7mm (IDxODxHeight) will do. Remember to replace the spring with rubber O-ring. NOK is the lip seal brand I used.
Any car parts or shop selling O-rings, bearings, oil seal etc...should have it. Otherwise online store like AliExpress has it too. Cheers!

Ken Y
 
Nov 6, 2006
9,202
Hunter 34 Mandeville Louisiana
Ken is right on.. that is a normal double lip oil seal.. available from CR, NOK, and other suppliers.. If ya want one that will last, you can special order from a bearing supply place like Motion Industries.. Hydrogenated NBR rubber and 316 ss garter spring will be about as good as ya get.. most regular ones are in engine oil service so have carbon steel springs which will last a few seasons, but will rust and make a mess as yours did..
 
Mar 20, 2016
490
Beneteau 351 WYC Whitby
Skf or daemar double lip Viton seal is what you what ,and they come with stainless garter spring .
viton Rubber Oils Seals are usually brown or reddish in colour and come with a stainless steel garter spring .They are well known for their excellent chemical and heat resistance up to 200 Deg celsius and to 260 Deg celsius for shorter periods down to -30 Deg celsius without affecting their elastic properties as a rubber. Resistance to common salt makes them an ideal marine solution and the great range of substances to which they are resistant like Aliphatic hydrocarbons,vegetable oils and fats as well as petroleum oils and greases, Chlorinated solvents, Acids and chemical agents, Ozone, Petroleum, Diesel etc make them a very versatile seal choice .
They are the only seals I use in industry for over 35 years and have changed out hundreds if not thousand of seals
 
Jun 25, 2004
282
Hunter 306 Pasadena MD
I appreciate the comments on the seal that failed. I want to point out that I think it can be a bit more difficult than you may think to find this exact seal online. With a wide variety of other [boat, car, lawn mower] engine parts, I have very little trouble finding a part supplier using Google or DuckDuckgo, or whatever. With this seal, not so much. Searching on "GACO DPSM 12247" yielded nothing useful. Knowing (from Ken's posting) that these numbers mean 12 x 24 x 7 mm, I didn't find much. Searching on "metric oil seal 12mm 24mm 7mm", I started to find some usable results. BTW, I've ordered a bunch of things from McMaster-Carr, and even in their metric seal section, I didn't see this size.

Anyway, as I said, I finally just called Depco Pump Company, and they only wanted to know the Johnson pump number F4B. In 3 or 4 days, they got the correct part to me for around $10, including shipping, which is just fine by me. I installed it and put the pump back together today, so... mission accomplished
After the fact, I noticed a few things:

1) Our gracious hosts, sailboatowners.com, actually stocks this part! Had I known, I would have ordered it from them to support the site. It took quite a bit of digging around for me to realize this, though. From some other site (I think it was Depco: http://depcopump.com/datasheets/johnson/10-24509-01.pdf), there is a part list which labels the lip seal as part number 05-29-139. On SBO, under Johnson Pumps Johnson Pump Replacement Lip Seals, they list "Johnson Pump Replacement Lip Seals, F35/F4" as part number "Mfg p/n 05-29-139", which agrees with the Depco diagram. So I'd say this is the right part.

2) Looking on the Motion Industries web site on Monday, I did manage to find one that had a stainless garter spring. But for the life of me, either they seem to have disabled their site since then, or I'm just too unintelligent to find how to display the list of more detailed specifications that I saw then, because I can't locate which one it is now.

Anyway, I bought one from Depco and installed it and it works without leaking. Since it wasn't all that difficult a process (given Ken's instructions), I'll just repeat it in another 16 years if this one fails. BTW: the new one has just the same markings as the last one:



new_seal.jpeg

Compare the picture to the old, ruined seal shown above: Still DPSM 12247 GACO. Thanks again for your comments and insights!
 
  • Helpful
Likes: tfox2069
Jun 25, 2004
282
Hunter 306 Pasadena MD
A couple of other observations (ok: 4) while I'm still thinking about it, partly referencing Ken13559's instructions.

1) I ended up just pushing the [oil] seal in with my fingers from the impeller side, after greasing it with Superlube. Didn't have to do the socket trick to seat it.

2) I also didn't replace the bearings, because they looked and felt fine, twisting the shaft in my fingers. My engine (and hence the pump) only has around 300 hours on it, so the bearings haven't really had time to get worn out. I guess they didn't get hit by any saltwater either: the water slinger (o-ring) seems to have done its job.

3) I was getting ready to remove the bearings to polish up the shaft (it needed it), when I realized: hey, you're not replacing them, so why take them off? I just covered them up with blue painter's tape to keep the grit out, and polished the shaft on a cloth wheel on a grinder using the very fine white rouge spec'd for stainless steel. If you have a grinder, you should definitely consider getting one of these wheels, as it's much gentler than using a wire brush (even a brass wire brush) on something like this shaft.

4) The bearings seem to be really, really sealed. So I don't have a clue how you'd go about greasing them. If I'm wrong about this, I'd like to know how.