m25xp pipe threads

[mdidomenico]

Are the pipe threads on the M-25xp metric?  i know the bolts are.  i pulled these fittings off my engine, the upper one was in the crank case breather hole and the lower was in the engine water flange.  the upper seems to thread into an M14 and the lower an M10.  i just want to make sure before i order new fittings.

i'm assuming yes, but i can't seem to find anything that explicitly states that.  i didn't see it in the manual (though i could have missed it) and these parts

https://shop.toadmarinesupply.com/ships_store/index.php?p=details&mfc=Westerbeke&sku=11471
https://shop.toadmarinesupply.com/ships_store/index.php?p=details&mfc=Universal&sku=301519

have no reference either. 

and to further, it seems my water pump is not metric though, 3/4" fittings seem to fit whereas the metric ones did not.

just double checking

[KWKloeber]

MD
Great question and oftentimes confused and/or answered incorrectly. 🤯🤬

[Edited]

The two ports that receive those fittings are not metric - they are JIS (Japanese Industrial Standard) pipe thread.

NOTE- the straight barbed fitting is NOT an 25XP OEM part and someone unknowingly? used an NPT fitting in the JIS threaded port (maybe on the water pump as well?)   That hose nipple is indeed in the parts manual and this is the OEM fitting





Rules of thumb;

Generally, any fastener that bolts into the Kubota block or anything supplied with the engine block to Universal Motors is metric.
(Examples -
The starter to the plate it attaches to are M8 bolts; the nut on the starter solenoid "B" post is M8 thread; the fasteners (bolts or studs/nuts, depending) holding on the sea water pump are M6.). Even the thermostat cap is by Universal, the bolts holding it to the Kubota water flange are M6.

Any pipe thread fitting that screws into the Kubota block or an OEM appendage (e.g., valve cover) is a tapered thread (like npt - National Pipe Thread) but is JIS thread.
Appendages added by Universal Motors (such as the sea water pump) are NPT thread (inlet/outlet.)

JIS is imperial sized (1/6", 1/8", 1/4", etc) and is functionally
equivalent to BSPT (British standard pipe tapered.) 
Example - the low-oil-pressure switch is 1/8" JIS thread? NOT 1/8 npt.

As I said JIS is an imperial size - (1/8", 1/4", etc.)  But the pitch (threads per inch) of the tapered pipe thread is different than our NPT thread. And the fit at the peak/valley of the two standards are very different (one rounded, the other sharp.)

Example -
1/8 JSI pipe is 1/8-27 (threads/inch)
1/4 JSI is 1/4-18
1/8 npt is 1/8-28
1/4 npt is 1/4-19

What's your goal regarding the two parts and maybe I can explain further, options, etc..
What are you trying to accomplish? with the sea water pump fittings as well?

Ken

[mdidomenico]

the goal is to replace the fittings.  the insides are caked with deposits.   the breather threaded elbow, i want to switch to a barbed fitting, i picked up an oil separator for that.  the barbed fitting from the engine water pump i could probably clean, but it looks like it's been hacked at a little or squeezed out of round (so now it's a trust issue).  the petcock in the top of the termostat housing i'd like to switch to half turn valve like mainesail suggests in his air-bleed tutorial.

the raw water pump fittings, i'd like to replace.  they're full of calcium and i don't understand why they're different or why one had a reducing bushing.  it would also be nice if they were sweeping fittings rather then hard 90's

all the other fittings on the engine seem okay, so i'll leave those be.  now that i know they're japanese thread, i'll look around for fittings.  doesn't look like mcmaster has them.

[Ron Hill]

mdid : Anything caked with calcium can be cleaned by soaking in Lime-a-Way!! 

A thought

[Stu Jackson]

the goal is to replace the fittings.  the insides are caked with deposits.   the breather threaded elbow, i want to switch to a barbed fitting, i picked up an oil separator for that.  >>>>>>>>>>>>>>>>

I rerouted my breather hose to the top of the air intake.  I just turned the fitting from its normal "down" position to horizontal facing aft.  Pictures of similar retrofits are in the 101 Topics, which you most likely have seen.  I do not feel that a barbed fitting is necessary because there is literally no pressure involved in this hose. I just used a hose clamp over the hose on the threaded fitting.  Ron's idea to clean it has merit.  You'll also find that soaking it in full strength Simple Green (nasty stuff!!!!) will do the same thing.

I also suggest you reconsider including the oil separator.  Why?  Because the idea is to get the tiny, tiny amount of oil in the line to the air intake, rather than trying to trap it and now having yet something else to clean and service.

As far as threads for the pump outlet elbows, check with www.depcopump.com.  Look up the Oberdorfer pump and find out the details there.  IIRC, Oberdorfer may also have a website with details of the pump or find it via Depco's website links.

I wouldn't sweat the 90 degree elbows, becasuse they are right at the pump, which can overcome their friction loss.  I've had elbows on my 1986 pump since our boat was new, they work just fine.

[KWKloeber]

MD see below

now that i know they're japanese thread, i'll look around for fittings.  doesn't look like mcmaster has them.

Here's one fact - you will find VERY FEW JIS barbs, elbow barbs, etc.  If you do it will be a very rare find.

JIS -- or you are more likely to see "British pipe" or "BSPT".  Either is unlikely to locate on this side of the pond, so good luck w/ that!

i want to switch to a barbed fitting, i picked up an oil separator for that. 

There's no need to have a barb, I clamped a hose (I think 3/8?) on the threaded ell - no muss no fuss for 15 years.   

I agree w/ SJ - rethink the oil separator -- why use one?  To exclude a whisp of oil from getting into a cylinder that burns fuel oil? 
There is one and only one argument to not run it direct to the air breather, and that is to prevent a run-away diesel.  I have NEVER heard of that happening on our diesels.  Yes. it is THEORETICALLY possible, but.....

barbed fitting from the engine water pump i could probably clean, but it looks like it's been hacked at a little or squeezed out of round (so now it's a trust issue). 

Truth be told, the PO already screwed up the water flange by tightening an NPT barb into the JIS port.  Because s/he was ignorant of the type and since the thread forms (TPI) are so close (27 vs 28) it seemed to be a correct fit.   

So replace with either JIS or NPT -- just use a good quality heavy-duty, high heat pipe dope.  If you want to go OEM, buy the Kubota hose nipple -- no barbs per se, but it is unnecessary.  The part number is in the Kb parts manual on the wiki. 

Atop the coolant pump - I'm not a proponent of mis-matching threads, but you can see that the NPT barb "worked" in the water flange.

YBYC whether to do the same on the pump, but the OEM part has worked for MANY years on MANY Universal and Kubota engines.  Why change to a different fitting?  Does the coolant pump have the OEM barb-less hose nipple?

You can get adapters - JIS one end, NPT the other -- M/M, FM/FM, and gender change -- (e.g., for into the coolant pump, then an NPT hose barb.)

valve

For the life of me, I don't GET the big deal about the valve on the T-stat housing -- prove me wrong but the argument for it seems to be "so I don't burn my fingers."  Ok, if you can't be aware and use a pliers or a rag when opening a petcock, I guess there's a benefit having a sexy quarter-turn valve.  But how often does one need to bleed?  This isn't a monthly or annual maintenance thing.  If there's an overflow reservoir -- once filled and burped there is no need to repeat it unless there is work done on the closed system.

I replaced crappy petcocks with brass ones that don't corrode/rust all to hell -- again, 20 yrs ago and no muss, no fuss since.

Remove the T-stat cap, drill out the 1/8" JIS -- and tap to 1/4" NPT for a ball valve?

While you have the cap off, add a hi-temp alarm switch (if you don't already have one.)

raw water pump fittings,
i don't understand why they're different or why one had a reducing bushing. 
it would also be nice if they were sweeping

Is yours a 1/2" or 3/8" NPT inlet/outlet pump?  I can't tell cuz the model tag is missing off the cover.

CatalinaDirect has 1/2" x 5/8 elbow barbs for the Ob pump.  Truth is -- they are simply 1/2 npt x 5/8" PEX adapters (that CD overcharges for.) 

You cannot have long sweeps or long barbs because the tip won't turn past the other elbow.  With nipples etc you can make anything work but it's not "clean."

I have sourced decent 90 elbows for YEARS -- and they do not exist.  I have bought a desk drawer full of tries and rejects that I will not sell with a pump.   Take my word for that or waste time researching it.
All have too little barb to double clamp and 99% are BRASS (a no-no.) 

The CDs elbows are brass as are the Wb/Sherwood elbows (what you have.)  I have one source that has GREAT marleon knock offs (but not in 5/8.)  I pleaded with them to make 1/2" x 5/8 barb -- "Sure," they agreed -- The first one is 14 thousand $$, very reasonably priced after that."

Can you C34-ers use straight-in barbs?  (IMO the best configuration.)   If so I have a solution -- if not, then just soak yours in Lime Away to clean up the deposits.

I ran the hose down from the pump outlet to the engine stringer and back up to the Hx -- I got really sick and tired of the hose being in the way of the oil dipstick.

[mdidomenico]

I probably will clean whatever i can and reuse.  i figured before i do if i can find new fittings relatively easy why not.  Since BSPT and JIS fittings atleast in barb form down under 1/2" seem to be hard to come by in the US and shipping from Japan or England is probably not worth it.

as for the thermostat cap, replacing the petcock is just a, eh its nicer, that's all.  the petcock that was there is frozen shut and doesn't seem worth cleaning.  but you're correct, i'll drill and tap the hole to NPT, the fitting seems like ALU, so it should be pretty easy to do.  i remember seeing an article about the temp sensor mod somewhere, i'll have to go back and read that.

as for the barb in the engine water pump, i'll likely clean and reuse.  without removing the part from the engine (which i don't want to do) i don't want to take a chance messing up the threads.  so i'll leave as is.

as for the raw water pump.  i'm not sure i have the correct/similar unit on my engine.  my threads are definitely 3/4". and the barb fittings are definitely 3/4" to 5/8" hose.  i've been trying to compare my model with the ones from depco/oberdorfer to see which rebuild kit i need.  i've been having trouble lining the specs in the data sheet for the 202-15 and my part.  i can only guess either, the PO upsized the pump or someone machined out the holes, for some odd reason.

[KWKloeber]

MD

first a couple corrections -

The T stat cap IS NPT -- 1/8" NPT -- remember it is NOT Kubota, it is Universal.  My point was to tap it to 1/4" NPT for a ball valve.

You definitely DO NOT have 3/4" NTP pump.  Pipe size (3/8", 1/2") is the nominal ID of the pipe, NOT the OD.  The actual ID can vary according to pipe schedule -- sch 10, sch 20, sch 40, sch 80 all have identical OD (the threads all have to fit together) -- the ID changes with heavier/lighter wall pipe.

Ob made/makes only TWO pump sizes for our engine -- 3/8" NPT in/out (202M-15) and 1/2" NPT in/out (202M-16.) 

NEARLY all Sherwood pumps were 1/2" NPT in/out.  One model was 3/8" NPT in/out.

Why you have one 1/2" npt and one 3/8" npt elbow?  Dunno.  A "P.O. job"?
It's kin to what I call a "buddy job."  ( My buddy did the (insert here - wiring, plumbing, carpentry, autobody, engine repair...) so I KNOW he wouldn't have screwed me on the (insert here - materials, workmanship, price).)

---- why do you want a rebuild kit -- is it leaking?  If you don't know what you are doing -- it's not HARD but is tricky to do it correctly.  Ron has a tech article.  AND you have to know whether the shaft is screwed up and needs replacing or can have it turned in a lathe to lose any score in it.  The easiest is to have Depco do a rebuild (YBYC.)

If you want just a new impeller/gasket/o-ring, they are:

6593             impeller
9797-034      o-ring (current N202M- pumps)
6599             paper gasket (older 202M- pumps)
Kubota  15296-88130 is the best mounting gasket.  If you can't locate one convenient I have about 25 in front of me.

Remove and deep six the cir-clip on the shaft it has no function and makes an impeller change harder.
Coat the shaft w/ superlube before putting on the impeller.  When you put the impeller in, it doesn't matter how the fins face -- they self correct on the first revolution.

Does your gear cover have 4 studs or does it mount with 4 bolts? It's been done both ways.

-Ken

[Jon W]

MD, another option is to leave the thermostat as 1/8" NPT, and install an 1/8" NPT m/f ball valve. Under normal operating conditions I have a 1/8" NPT plug in the ball valve. When I replace the coolant I remove the plug, screw in a hose barb with a clear tube attached and bleed the air. Works fine. A couple of photos attached for reference (there is a small gap between the crankcase breather hose and the ball valve) .

For stubborn air blockages I remove the hose from the bottom of the thermostat housing and use a small hand pump to pull the coolant through the system, then bleed again through the ball valve.

[KWKloeber]

MD
I forgot to mention the hi-temp alarm switch.  New Universal T-stat caps have a 1/8 NPT port, but you can drill/tap an old cap. 
https://www.catalinadirect.com/shop-by-boat/catalina-38/electrical/high-temp-alarm-retrofit-m-18-m-25-m-25xp-m-35/

Zoom in on below and you can see the switch sticking out the stbd side.  Drill/tap a hole about 3 o'clock so it doesn't interfere with the temp sender or cap bolt.
You can drill now and plug it and install the wiring anytime down the road.   Any questions just hollar.

[mdidomenico]

The T stat cap IS NPT -- 1/8" NPT -- remember it is NOT Kubota, it is Universal.  My point was to tap it to 1/4" NPT for a ball valve.

oh, sorry i misunderstood.

You definitely DO NOT have 3/4" NTP pump.  Pipe size (3/8", 1/2") is the nominal ID of the pipe, NOT the OD.  The actual ID can vary according to pipe schedule -- sch 10, sch 20, sch 40, sch 80 all have identical OD (the threads all have to fit together) -- the ID changes with heavier/lighter wall pipe.

the 3/4" i referred to is the size of the fittings threads.  of which they definitely are.

Why you have one 1/2" npt and one 3/8" npt elbow?  Dunno.  A "P.O. job"?
It's kin to what I call a "buddy job."  ( My buddy did the (insert here - wiring, plumbing, carpentry, autobody, engine repair...) so I KNOW he wouldn't have screwed me on the (insert here - materials, workmanship, price).)
---- why do you want a rebuild kit -- is it leaking?  If you don't know what you are doing -- it's not HARD but is tricky to do it correctly.  Ron has a tech article.  AND you have to know whether the shaft is screwed up and needs replacing or can have it turned in a lathe to lose any score in it.  The easiest is to have Depco do a rebuild (YBYC.)

i was looking for a rebuild kit for that exact reason.  i have no idea whether the PO ever serviced the pump to the level in the 25yrs he owned the boat.  it sat on the hard for five and has now for two for me.  figured it'd be a good idea.  the shaft looks okay.  there doesn't seem to be any noticeable scoring or insets through wear.  there also doesn't seem to be any slop in the shaft when set in the bearings.  i have a micrometer, if the measurement is somewhere i can check it

Does your gear cover have 4 studs or does it mount with 4 bolts? It's been done both ways.

if you're referring to how the pump sits on the engine, it has four studs.  the nuts were almost completely corroded off, but the studs seem okay.

[mdidomenico]

MD
I forgot to mention the hi-temp alarm switch.  New Universal T-stat caps have a 1/8 NPT port, but you can drill/tap an old cap. 
https://www.catalinadirect.com/shop-by-boat/catalina-38/electrical/high-temp-alarm-retrofit-m-18-m-25-m-25xp-m-35/

Gotcha, seems like a good idea.  I'll have to see if i have a tap of the right size

[KWKloeber]

MD

The wear on the pump shaft will be at the carbon bearing and/or at the lip seals.  So use the remainder of it as your guide.  The master rebuild kit you need is the one for the 202M-15 or 202M-16. 


You need 1/2"npt x 5/8" elbows, CD has them (they are PEX elbow fitting if you can find for half the price them elsewhere)  Will straight-in barbs work on a C34?


There are also other less expensive hi-temp switches out there

amazon.com/dp/B07QBHJPFV


Both the temp SW and the temp sender MUST have a good so I recommend copper-based never seize, and a good star lock washer under the bolt head to get a good bite.  Paint over the head/washer afterward to keep out corrosion.   Or bond the switch or sender (as I do on harness jobs.)

[mdidomenico]

You need 1/2"npt x 5/8" elbows, CD has them (they are PEX elbow fitting if you can find for half the price them elsewhere)  Will straight-in barbs work on a C34?

are these bronze or brass?  perhaps i misunderstood.  i thought brass fittings (which i believe most pex fittings are) on the raw water side of things was a no-no.  my thought was to see (as you suggest) whether straight fittings will work and then pickup some bronze fittings from groco.  i believe the straights will fit, i'll just need a little extra hose to soften the bend.  and i guess it'll look a little funny, but i don't care about that

Both the temp SW and the temp sender MUST have a good so I recommend copper-based never seize, and a good star lock washer under the bolt head to get a good bite.  Paint over the head/washer afterward to keep out corrosion.   Or bond the switch or sender (as I do on harness jobs.)

my temp sender doesn't seem to thread in any where near far enough to have a starlock washer between it's shoulder and the housing.  after five/six turns it tightens up solid like an npt fitting and there's still 1/4 or 3/8 of thread sticking out.

[mdidomenico]

successfully taped the temp switch in, changed the 1/8" petcock to 1/4" ball valve, and ran the 1/4" npt tap down the temp sender hole, so now it sits more flush against the housing.  i still need to put sealant on the threads and screw them down tight, but i left the sealant down at the boat