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Author Topic: M25XP problems  (Read 8409 times)

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Mike and Theresa Vaccaro

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M25XP problems
« Reply #15 on: November 26, 2003, 06:07:23 AM »

Would like to suggest that folks with repair manuals for the various versions of the Universal engines in our boats consider scanning them and providing them to the webmaster so that we'd have on-line access.  
 Have found the Torrison site to be one of the best diesel repair resources on the web, but since we've got a limited number of engine types, there's no reason we couldn't consolodate some of the experience of our members in our own "diesel repair forum."
 Unfortunately, I don't have the computer equipment or skill to pull this off, so I can only offer a suggestion!  But if there is anyone on the board with the time and inclination to do this, perhaps we could all find a way to contribute.
 Since their aren't any mechanics at sea--we have no choice but to be our own engineers.

Ray & Sandy Erps

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M25XP problems
« Reply #16 on: November 26, 2003, 10:43:51 AM »

 Might be worth giving that original mechanic another call and asking him what the compression readings were for each cylinder.  He might have even written them down on the valve cover with an indelible ink pen.  If he can tell you what the values were, it would increase my confidence in him/her a bit.  Generally speaking, compression values should be within 10% of each other.
 Generally speaking again, a compression test is done by holding the tip of a pressure gauge tight against the fuel injector hole.  Usually takes two people, one to hold the gauge, the other to crank the engine.  Pop out all the injectors, hold the gauge to one of the injector holes, crank the engine around a few times then record the reading.  Repeat for the other cylinders.  That’s the dry check.  If you find one cylinder with compression considerably lower than the other cylinders, squirt some oil down that injector hole and crank the engine a few revolutions so the oil can coat the cylinder walls.  Check the compression on that hole again.  That’s the wet check.  A substantial increase in compression on that “dead hole” would indicate that the rings aren’t sealing well on that cylinder.  Little or no increase would indicate that the compression is leaking past the valves or headgasket.
 Diesel engines develop a considerable amount of pressure in each cylinder.  My recollection is that pressures may be around 400 psi, compared to an old V.W. engine with compression around 110 psi.  So it will take a beefy compression gauge to do the job.  The fuel systems in diesels also develop some high pressures to inject the fuel into the cylinders.  Need to be careful working around those injector lines while doing the tests.  Pulling the fuel shut off cable should take care of that problem.
 A quick and dirty compression test technique that I use when kicking the tires on a used car or boat is to disable the ignition system (pull the fuel shut off cable) then crank the engine a few revolutions.  Because you’ve turned off the fuel, it won’t start and you can listen to the motor as the starter cranks it through several revolutions.  What you’re listening for is an even cadence in cranking or the sound of any high pressure air escaping the valves in the case of an uneven cranking sound.  Hard to judge the value of that test, but it’s a test that I’ve used for over twenty years and I’ve been able to identify some motors with compression problems doing it.
Ray & Sandy Erps,
'83, 41 Fraser "Nikko"
La Conner WA


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M25XP problems
« Reply #17 on: November 27, 2003, 03:34:16 PM »

Found this page surfing around.
 Offers rebuilt kubota engines for less than $3K. One would need to remove alternator, raw water pump, exhaust maniforld, etc and then reassemble, but sholdn't be difficult.
 Just a thought,


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M25XP problems
« Reply #18 on: November 28, 2003, 12:46:23 PM »

 In your first post you mentioned that your engine is a M25XP.  The service bulletin regarding the cam sleeve at the C36 website says the the effected engines in the M25 series are the M25XPB and M25XPBC.  You should be able to read the bulletin carefully and determine if your engine is effected.  (I doubt it because of the age of your boat).  Below is a link to the website:
 Good Luck.


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M25XP problems
« Reply #19 on: November 28, 2003, 04:51:05 PM »

 Another approach is to find and eliminate the source of the water ingress and deal with that issue (is it exists) and then run the engine until it no longer runs.  Replacement at that time, perhaps years down the road, will be less stressful.
 You indicated that you are a stones throw from sailing waters.  That leads me to believe that you only need the engine to get in and out of your slip.  If low speed stalling is a major problem, increase the idle.  I get the feeling that no one has a clue as to the root cause of your problem.  Doing nothing may be an acceptable course of action at this juncture.
 Jim Kane


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M25XP problems
« Reply #20 on: November 30, 2003, 11:44:41 PM »

We spent half of Sunday poking around the engine, checked a few things out and confirmed the following:
 .  there is grey oily gunk all around inside the valve cover - looks awfully like an oil/water emulsion
 .  the Sherwood raw water pump looks original, with a lot of rust on the mounting tube (don't know if that's the correct terminology) behind the pump casting (we didn't want to dismantle the pump in case everything fell apart on us because of the rust)
 .  drained a cup of oil from the sump - it appeared to be clean black oil with no water in it
 .  the dip stick oil is also clean, but the level is above the full mark
 .  we were not able to confirm or otherwise the reported low compression in the middle cylinder
 What do you guys think of Our conclusions:
 .  with the rust on the water pump mount, it looks as though the pump shaft seal has been leaking (although this might have been due to a previous episode, as we had not noticed any water under the engine until the current problem) - but the weep hole may be blocked
 .  if the water/oil gunk is restricted to the top of the engine, the water leak is where it can only get to there, and not down into the crankcase, and is slow enough for the water to vapourise in the cylinders when the engine is running - but ... why isn't the sump oil being pumped up and flushing the gunk down into the crankcase?
 While we were on the boat, Max Cooper (Fandango) came down the marina to introduce himself and offer us the name of a mechanic has had good experience with.  We have contacted the mechanic to seek another opinion on fixing the problem.  
 At this stage, until we are convinced otherwise, our inclination is to get a mechanic to take the head off with the engine in the boat, clean up and inspect, particularly checking if a blown head gasket may be involved.  If necessary replace the complete raw water pump, or at least the seals and the mounting tube.  Also inspect valves and seats in case this is the cause of low compression in the middle cylinder (which still needs confirmation).  
 If the inspection suggests the gunk has got further down the engine, I guess we then are faced with removal of the engine for a strip down and rebuild - in which case we also consider replacing all wear components in order to get value from the labour cost of the exercise.  That way we would hope to have an engine good for many more years.
 We also need to look carefully at the heat exchanger - there is corrosion on connection points.  I seem to recall previous posts that may assist on this one.
 So, we are waiting for another mechanic's opinion until we decide what to do.  Grateful for any further comments and suggestions in the light of what we have found so far.

Ken Juul

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M25XP problems
« Reply #21 on: December 01, 2003, 05:33:39 AM »

I think you have a combination of simple problems.  The overfilled oil will cause foaming of the oil in the pan.  This foam will seek escape through the breather causing it to collect in the valve cover gasket.  Internal combustion process makes water, unfortunately I don't remember the chemical process.  The oil absorbs this water.  As the oil heats up, it releases the water vapor which also tries to exit the engine through the breather. I think these are the cause of the gray mess. You said you only use the engine in and around the dock, I would assume that is mostly low engine speed maneuvering.  Idling a desiel for extended periods causes the engine to load up with carbon.  I think this is the cause of the poor idle.  If it were me I would change the oil/filter.  Fill to the proper level and then go motoring.  Let the engine get up to temp and then work it hard for an hour or so.  If it is still running poorly when your finished, get the second opinion.
Ken & Vicki Juul
Luna Loca #1090
Chesapeake Bay
Past Commodore C34IA


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M25XP problems
« Reply #22 on: December 01, 2003, 01:06:09 PM »

  Good job,I think your on the right track. Water, if any, is in the crankcase  will not necessarily hurt the engine ( probably not at all ) . Just change the oil and filter. Water (oily mess) in the top of the engine can be cleaned by removing the valve cover, and the mess removed with a rag ( WD-40 can be sprayed into the hard to reach areas ).
 I would never start an engine and shut it down without the engine reaching the proper operating temperature ( to burn off condensation ). This will prolong the life of any engine.
  Please have a compression check done prior to any other engine work! A good mechanic can do this. If a cylinder is low he can do a cylinder leak test. This is done by filling the cylinder with compressed air (like a tire inter tube) to isolate the leak i.e.valves, head gasket, or rings. Good luck,


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« Reply #23 on: December 04, 2003, 05:16:43 AM »

I hear those of you with the M25XP mentioning a 'fuel pump filter'.  I have an M35B, does anyone know if the M35B has this fuel pump filter??  I only know of two, the Racor and the engine filter.  Where's the third??
Roc - "Sea Life" 2000 MKII #1477.  Rock Hall, MD


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M25XP problems
« Reply #24 on: December 04, 2003, 02:26:02 PM »

It's a screen that's inside the fuel pump itself.

Bob Mack #52

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M25XP problems
« Reply #25 on: December 04, 2003, 05:09:26 PM »

Steve is correct and I should have been a bit more clear in my description. I'm not sure about later boats, but mine (Hull #52, M25 engine) was configured such that the fuel flow came first to the electic fuel pump with it's built in screen. From there the fuel went to the primary filter (Dahl - in my case, Racor in many others) and then on to the engine mounted fuel filter. Early on I, like many, changed this routing such that the first line of defense is was primary filter and then on to the electric fuel pump. Having done that, the 'screen' filter in the electic fuel pump mostly became irrelevant because the primary filter was far more discriminant in filtering. But it's important, and very easy to check out and clean, the screen within the electic pump in case it's clogged. One other thing to consider is the fact that the fuel pickup tube within the tank also has a screen assuming the PO hasn't already removed it. Again, relatively easy to check and clean. Personally I have mixed feelings about removing that pickup screen as many have done.

Stu Jackson

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« Reply #26 on: December 04, 2003, 07:56:16 PM »

RACOR and fuel filters
 Find on racor:
 with lots of sidebars on fuel filters, etc.
Stu Jackson, C34 IA Secretary, #224 1986, "Aquavite"  Cowichan Bay, BC  Maple Bay Marina  SR/FK, M25, Rocna 10 (22#) (NZ model)

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