Frozen raw water pump shaft

[dillehay]

     We have a 1991 MKII with an M34B Universal and a Sherwood raw water pump in which the shaft has frozen, which we discovered after checking for the usual problems that could prevent raw water discharge at the outflow—clogged intake; full strainer; obstructed hoses to and from the pump through the system; broken impeller.  The problem appeared suddenly, though now in retrospect it appears that some rust around the weep holes should have been a warning.  The problem showed up after the boat sat for about a month; previously we had sailed nearly weekly, using the engine 10-15 minutes to get in and out of the harbor.  We routinely check for raw water exhaust at start-up and when the engine is in use.
     We purchased the boat new in 2001, and the engine has been professionally serviced annually, including a routine changing of the impeller.  The impending problem was not detected previously, even though the most recent service was June of this year.  In addition, while tracing down an overheating problem in early July (turned out to be a clogged heat exchanger), a highly-regarded engine mechanic did not notice a problem with the pump.  In any case ...
     After discovering the frozen water pump shaft we were concerned about damage to the camshaft.  We checked to determine that the camshaft turns.  It does.  We thought it would because the engine has never given any indication that a problem of any kind existed.  Starts fine, no misses, responds to throttle changes.  What appears to have happened is that the water pump shaft was driven forward in its housing enough to permit the cam to turn unimpeded, this after some damage to the key on the water pump shaft that fits into the slot at the camshaft.  There may also be some wear at the slot on the end of the camshaft, but we do not know if the slight concavity at the slot is normal or not.  Can anyone tell us about that?  That indentation appears to be about 1/8th of an inch or so at its maximum at the slot itself and does not extend to the edges of the camshaft.  By appearance it could have been created by rubbing against a somewhat displaced, frozen water pump shaft.  The slot at the end of the camshaft clearly has most of its depth, which seems plenty to engage a properly inserted water pump shaft.  We don't have the new pump yet so we have not measured that fit.  We are inclined to determine by measurement on a new pump that the shaft inserts fully into the slotted end of the cam and to install the new pump.  Any thoughts on this or alternative actions would be appreciated.

[Ron Hill]

dill : It sounds to me like you are missing the Westerbeke modification of the sleeve that goes over the engine cam to Sherwood shaft connection.
You might want to talk to Westerbeke or your local dealer.  It's posted on our site and published in the Mainsheet!   A thought

[Stu Jackson]

http://www.westerbeke.com/Products/ProductServiceBulletins.aspx?ID=8

http://www.westerbeke.com/ServiceBulletins/sb_235.pdf

I've found that the phrase "highly-regarded engine mechanic" may be an oxymoron.  There may be a few out there, and in the past I've raised this issue and a few individuals have had some success.  My experience: learn do it yourself.

Our Critical Upgrades sticky here on the board, and also on the C34 Tech wiki recommends reading and acting upon those bulletins.

While you report you have a 2001 C34, there's no reason to believe that your engine may not have been built before January 2000.

[sail4dale]

It happened to me in my 2001 model and it sheared my hoses by twisting the hole pump.

The cam shaft was OK and a new pump solved the problem.  Ironically I had an appointment with the mechanic to check out the pump on the very next day

Good chance you are OK

[Stewartn]

INMO, the basic Universal (Kubota block) engine is fine and durable. It's the questionable engineering of the raw water pump (Sherwood ). You all may remember my '09 problem with sea water in the engine caused by a bad seal in the Sherwood pump. I do trust my mechanic. His view is that in a salt water marine environment, the SAFE WORKING LIFE of that Sherwood is about 5 years. After that it should be removed and rebuilt or replaced based on cost. It's the only way to really prevent problems. Mine was new in '09 and in 2014 it will come off for a rebuild.

[pablosgirl]

Hi Dill,

You may want to consider replacing the Sherwood with the Oberdorfer pump.  The Oberdorfer pump has a carbon bearing around a bronze shaft.  They won't lock up, just leak salt water out the weep hole and rust out your oil pan.  The Tech Wiki has an article about swapping the Oberdorfer for the Sherwood.  You can find it here http://www.c34.org/wiki/index.php?title=Replacing_a_Sherwood_Water_Pump_with_an_Oberdorfer

[Ron Hill]

Paul : Let me help you out a bit. 
The carbon cylindrical tube on an Oberdoffer pump is a centering bushing to keep the stainless shaft - centered.  In 5000 hrs I only replaced that bushing once, so it has long life.

The safe working life is not only measured in years, but also in use (engine hours)!
I'm not too sure that us civilians can change out items just based on time, rather than waiting on them to give signs of failure? 
When was the last time that you went below and looked at the raw water pump weep holes, drive belt running and just generally inspected that running engine???  Ever look back and count the drips of the packing gland?  You can easily see the water dripping from the gland or RW pump and when it's running is when it really counts.
That is the best preventive maintenance you can do and it's so simply done!!  A few thoughts 

[Stu Jackson]

Ron's right.  Our Critical Upgrades topic, #13 is entitled:  Careful Engine Inspection.  For those of you who have your engines maintained by "trained professionals" you might do well to check "under the hood" sometimes yourselves.  I say this only to make the point that boat engines are not like automobile engines.  Except for those of us who used to and may still work on their own car engines.

[Stu Jackson]

1.   You may want to consider replacing the Sherwood with the Oberdorfer pump. 

2.  (a) They won't lock up,

2.  (b)  just leak salt water out the weep hole and rust out your oil pan. 

1.  I would if I had a Sherwood.  If simply for the access issue.

2.  a. Maybe.  b.  My old Oberdorfer DID leak.  They HAVE TO because that's what weep holes are for.  That's how I learned to "Change My Seals Before the Oil Pan Rusts Out" when we first got our boat.

[Norris Johnson]

I have some experience here. I had to replace the cam shaft on two universals 35Bs in 2001. It is well documented on this website. Universal supplied all the parts, but no mech. I did it myself. I do have experience with a number of different engines. I strongly recommend changing the raw h2o pump and installing the sleeve Ron spoke of. Hopefully the cam shaft isn't worn too much. The sleeve is very important. Never had any more trouble with either engine. I just changed the raw h2o pump whenever I saw any leakage.
Good Luck!

[dillehay]

The critical upgrade sleeve over the end of the camshaft was in place when the frozen shaft on the raw water pump was discovered.  What puzzles all hands is that the engine never showed any sign of a problem and there is little damage to either the end of the cam or the tang on the water pump shaft.  It is as though one or the other of the shafts was displaced to permit the engine to turn over normally while that shaft was frozen, resulting in little damage to either the tang or the slot.  One speculation is that there was very little overlap between the cam and the pump shaft where they meet, i.e., the tang on the shaft did not extend far into the slot on the cam, allowing some wear on the cam end and the shaft rather than something breaking, like the fasteners holding the pump to the block.  We are going to measure carefully the extension of a new pump shaft and position of the end of the cam.  It is almost as though one of those shafts is too short or misassembled.  Hard to imagine the cam is not correct given the good performance of the engine.  But it also is evident that the shaft in the pump does not have a lot of in/out play. 

[Ron Hill]

dill : Part of my original recommendation stands.  Get hold of Westerbeke and let them know your problem.  Hopefully the yard/mechanic is a Westerbeke dealer.

I'd take pictures and document your every move and put the problem in their lap.
 
I'd also call Joe Joyce and solicit his help and give him the complete story + photos.
 
The only confusing part of your story is the "instant" failure.  It seems like it should have been a gradual type thing. 
Only a few drips of salt water will cause rust, so a note of rust on the Sherwood is of no consequence unless it was dripping.  i.e. A drop of salt water on a unpainted engine mount will rust if not wiped off.

Pleas keep us posted on your progress.  Best of luck.