Messages

Fuzzy, Mregan, Ron, thanks for your comments.  I will pursue them.  One concern I have is that a blockage beyond the exhaust manifold would create a back-up that could put water into the engine--much like trying to start the engine for more than 30 seconds.  Could this happen?  We already know water reaches the nipple at the exhaust manifold.  And it is reassuring that no water ran back out when we disconnected the hose from the output side of the siphon. 
     One thing I should have included in the original post is that there is the "swoosh, swaash" sound from the muffler area when the engine is running.  Much like the normal sound when things are operating correctly.  I did not try to pinpoint the source--muffler, pipes--at that time.  Probably means, given what else we have eliminated as possible causes of the failure--that water is reaching the muffler but not exiting.  But why it would not then back up the hose and pipe to the exhaust muffler?  Maybe that would take longer than the amount of time the engine ran?
     I'm thinking I should get a CO detector since there could be an exhaust leak into the aft cabin (part of the problem?), and we are at the point in the search of looking at and beyond the exhaust manifold.  Maybe the exhaust fan would take care of this concern?  Has there ever been a CO issue in the aft cabin that anyone knows about?
Thanks, Ron

Larry,

Because the water output was so low I did not run the engine beyond the point when it reached 160 and began to climb after that.  I basically stopped when the temperature began to rise above what has been normal.  Should I allow it to rise further?  Any possible damage being created if I did so?  That was my concern.
Dillehay

We have a 2001 MKII with less than 500 hours, and the raw water output was extremely low when I started her up recently.  Water output is down to about 1/10th normal.  Exhaust fumes come out.  Trouble shooting so far we have checked or done the following:  the intake water filter didn't need it much but has been cleaned; water was determined to flow freely through the intake through-hull valve; the port-side cap at the end of the heat exchanger was removed and the interior found to be free of debris and looked clean; the pump impeller was replaced (though the old one looked OK; this has been done annually); we disconnected the hose from the output side of the siphon down stream from the heat exchanger and water flowed freely with the engine in idle; and with a flexible probe determined that the hose from the siphon to the exhaust manifold is clear.  Because there are no water leaks that show up in the bilge or anywhere we can see along the system, and because inspecting the water flow through the transparent top of the intake filter looks like there is very little flow, the problem is apparently a blockage or failure somewhere after the exhaust manifold.  We ran out of time in our search, but will take it up again soon.  Any thoughts, cautions, or suggestions?

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. 

     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.

With the boat hauled and a shaft replacement underway, the dripless PYI packing gland has been suggested to replace the original, conventional packing gland.  I'm told all new boats come with the dripless system, and that it is essentially trouble-free.  I'd be interested in any observations/recommendations from those with experience with the system.

On hull #1576, a 2001 MK II, which I bought new, I have discovered extensive corrosion on the shaft between the strut and the cutlass bearing.  Has developed in the last 3 years, during which time I have attempted to maintain zincs by a 2-month inspection along with bottom cleaning.  When last hauled there was no evidence of any issue.  The strut is fine.  Anyone with similar experience?  Thoughts?