Pulling!

I used a gear puller set I bought at Harbor Freight to Remove the harmonic balancer.  The impact wrench I bought with the hope it might shake the crank loose had no effect, but it did a great job taking off the bolt that secures the pulley.  Then It was pretty simple to attach the gear puller behind the harmonic balancer and pull it off the shaft.  Reinstalling the bolt gave me a nice spot for the tool to push against.

Getting the water pump loose

I also worked the water pump housing free.  It was stiff and held on by mostly paint and goo.

The high pressure fuel pump was also removed.  There is a low pressure one, too.

The allen key here was used to remove the bolt. I don’t know if it secures the pin or the shaft itself!

I removed the screw that holds allen screw on the end of the crank start but could not get the pin out.  It didn’t seem to want to drift loose or unscrew.  The only reference photo I have is the black and white shop manual photo but that is from a slightly different engine.

Engine Work

I did about 90 minutes’ work on the motor, using a pair of vise grip pliers to loosen the a stubborn bolt holding the water pump housing to the motor front plate. The same pliers were great for removing the water pump impeller cover screws; all but one were stripped and/or frozen. Next, I loosened the hose clamps securing the seawater plumbing and gently pried the cover off. The impeller had all its rubber vanes but there was a lot of build up on them and it was clear they weren’t moving. I was able to pry off the impeller, but the rubber piece separated from its bushing, which I removed separately. The motor still could not be turned at the crankshaft, so I will need to continue the disassembly.

I wonder if the seawater that got into the engine sump entered through the water pump, intake or exhaust ports?  The exhaust path is most logical, back from raw water burped through the water lift muffler into the exhaust port (if the engine was run with the starter without ignition), but it was the intake valve that was frozen, suggesting it was somehow involved.

I took another look at the Yanmar service manual, and see I am a good ways toward having the engine torn down. With the head already off and the intake and exhaust assemblies disconnected, it’s just the fuel pump, separator and a couple lines before the V pulley comes off, at which point it should be possible to remove the front and side covers from the engine and get a very clear view as to what has the motor siezed. I suspect at this point it is just the piston rings frozen to the cylinder walls, but worst case it could invlove the crank or camshaft. Time will tell. Then some informed decisions can be made about whether a partial rebuild or repower is most appropriate.

It will be a good project for this Saturday before I plan to do some stabilization of the trailer, and possibly pull the mast down on next Sunday.

Looking forward at the Yanmar SB-8 from the aft (transmission) side. Large loop is the engine lift/throttle mount. To the right the exhaust port of the cylinder head is visible with one bolt in place to keep the oil in. In the background, a rat’s nest of wires that will need some attention.

I spent almost four hours on the motor on Wednesday.  The level of the automatic transmission fluid I was using to soak the cylinder had not dropped much, so I decided to proceed with the head removal. After much effort I was able to get the cylinder head off.  The throttle linkage mounts to the head, so that had to be removed with two large bolts.  The 1/2 drive metric sockets I picked up yesterday at Harbor Freight came in handy for this.

I was able to separate the head gasket and slowly work in a small wood shim between the head and engine.  It didn’t want to go further.  As it turns out, there was some significant rust on a pair of the studs that made the fit very difficult. It took an hour to pry the head off, working bit by bit from three sides of the engine, even though all the fasteners were removed.  I was concerned that the clearance between the top of the studs and the cylinder head, which still had the injector installed, wouldn’t give me space to remove the head because the cockpit is directly above.  Luckily it cleared by a fraction of an inch in a very particular orientation I hope I can remember if I reinstall it later.

The exhaust valve looks and operates fine, but the intake valve was siezed, and even tapping on it with a wood block did not allow it to move. The corresponding pushrod was also rusty.

Disaster!  When I put one of the pushrods back in the engine block I must have missed the rod channel and dropped it right into one of the oil passages.  This necessitated removing the oilpan, which is held on by nine 10mm bolts.  I began by draining the sump, and was surprised to find about 8 ounces of water at the bottom of the bilge.  That pretty much explains all the problems with the engine.  The water and goey tarball oil went right into the bilge to join the diesel already there.  The pan came off fairly easily after breaking the bolts loose with a small 10mm box wrench.  The cheapie 1/4″ drive socket broke off on the first one.

Inside the bilge I found another half cup of oily goo and the errant pushrod, which had fallen straight through. I cleaned off the underside of the engine, and felt the oil pickup and the bottom of the dipstick, which is a very odd texture if you’re not expecting it… felt like a big tye wrap hanging down.  Nothing I could reach seemed rusty, though. Oil pickup tube and the bottom of the crank.  I expect the problems now are in the middle front areas, where the water and diesel pumps are.

Next, I tried to remove the water pump, but 1 of the three 10mm screws was very corroded and will require vice grips and a prayer. The others came straight out.  A project for later this week!

At this point I am expecting I will need a new engine, and the Yanmar 2GM-20F looks like a good bet.  That model is a 15HP twin-cylinder, freshwater-cooled engine.  I would benefit from both the added horsepower and the freshwater cooling, which would actually permit the use of the water heater I already have, if I can find a place for it.

a 5-foot section of blue formica I found at Restore in San Carlos for $20. A little dusty, but vaguely nautical.

I picked up two boxes of 4″ slate tile at the restore center to evaluate for the furnace area.  I also bought a 5′ section of sea-blue formica for $20 for the galley.  I don’t know if this is the final counter, but I figured it would be best to make all my mistakes with an inexpensive piece of material (Like getting it up the ladder, through the companionway and onto the table surface isn’t an adventure in itself.)

Oh – I didn’t like that tile much.  I packed it up to return on Thursday.