My first PWC Season came to a frustrating halt in mid-September. The 580cc Rotax engine in our Sea-doo had seized in the middle of Possum Kingdom Lake. My wife thought I was playing around as she passed me on the lake, only waiting until she was a little dot on the horizon before turning around to look for me. I was sitting dead in the water, cussing and swearing. It was a beautiful day, 80+ degrees, sun shinning high in the sky, just enough chop on the water to cut the glare and I am sitting still, bobbing in the middle of a lake, 75 miles from home.

    My brain had already started into diagnostic mode, 'What was that screeching sound', 'Why does the motor not turn over when I hit the button'.  Little did I know at the time, what had happened.  After what seemed like a hour long tow back to the launch ramp, I start taking the spark plugs out. Without the compression the starter motor has enough power to turn over the motor. But my initial happiness is squelched by the bits of metal flying out the spark plug holes.  Something has come apart inside the motor. 

    After getting the boat home I start to work on finding the source of the awful clicking noise coming from the motor, when I turn it over.  An hour later, I was pretty sure it was coming from the intake side of the motor.  With that, I started looking at the Clymer's Shop Manual and noticed the rotary valve was on that side of the motor, with a brass gear that drives this valve from the crankshaft.  I knew then that I was in for an expensive repair. 

    Prepared for the worst and hoping for a simple and cheap repair, I removed the engine from the boat and moved it to the work bench.  This removal was not easy but I did fabricate a few tools that helped.   The best tool was a hoist that I fabricated. My garage is open to the second floor, and I built a hoist to lift the boat off the trailer and suspend it a various heights.

    With the boat suspended, I could get the exhaust and jet pump off the engine and prep it for engine removal.  Once the intake manifold was removed from the engine, it was easily lifted out (but still heavy).

    The next challenge was tracking all the fasteners. There were screws, bolts, washers, and nuts, zip ties, and hose clamps.   With some careful use of masking tape, I kept all the fasteners in the mounting holes as I removed the components.  For the odd stuff, I purchased some baskets and tilt-bins.

    With the engine on the workbench, the damage was pretty apparent.  The rotary valve was damaged with a circular crease and a bent in the leading edge.  The machines surface of the crankcase where the rotary valve rotates on, was scared with a groove that matched the deformed leading edge and crease in the rotary valve. The intake ports on the crankcase were damaged as the bent leading edge of the rotary valve collided with port opening.  With some work the Crankcase could be honed and smoothed out, but what caused the bent in the rotary valve?

    Tearing the engine down like a normal 'top-end' was fully documented in the Clymers shop manual.  The head cover, then the head were removed.  Inspecting the head revealed pits were the bits of metal from before had bounced around inside the #2 cylinder. There were also pits on the crown of the #2 piston.  These pits could be from the material removed from the crankcase as the rotary valve did it's damage.

    Removing the #1 cylinder from the crankcase wasn't to bad, but the #2 was some trouble.  After getting it off, it was obvious why.  The #2 cylinder wall had a scar it in that matched a scar on the piston sleeve/skirt.  This was probably the cause of the screech I heard on the lake.

    With the removal of the Pistons from the rods, the cause of the break down became apparent.  The #2 rod had burnt and destroyed a Crank/Rod bearing.  The #2 rod was very loose when compared to the #1. I took the engine in to my Sea-doo Shop, and they confirmed it. The lower Rod bearing had come apart and pieces ended up between the cylinder wall and piston, and a piece was ejected out the intake port, where it collided with the closing rotary valve. This collision caused the bend in the valve, and the damage to the crank case. 

    This is where I stopped thinking about it for the winter.  I was really bummed that the boat I just purchased had broken down so badly.  If it had been the '89 Yamaha, that had failed, that wouldn't have been so bad.  It is the older boat, with the most wear and least maintenance.

    Spring is starting to spring, and it's warm enough to get back into the garage.  Luckily, the Sea-doo's still waiting for me.  Getting the estimates from the dealers on parts and labor, it looks pretty grim.  Part alone are looking at LEAST $800, and labor could easily be 500 more, just to replace the crank and bolt it back up.

    Spring has sprung and it's time to do something, work was getting to be a real pain, and I need my liquid therapy.   After lookig at the quotes again, I decided to get a rebuild short block and have my dealer put it in.  This way I would have a relatively new engine, and albeit a short one, a 30 day warenty.  Neither of these things come with a crankshaft replacment.

    Being Spring, there was a wait at the dealer, but they did their best to get me in and out.  The ordering of the short block was to take 10 days, but arrived in 3. They thought there was to be a 2+ week wait on getting my work order to a mechanic, but they had me out in 6 days. 

    What a great feeling, to tow home my reason for going to work every morning (and my reason to play hooky)!!!  The night before I had finished replacing the bunks on the trailer, and the Sea-doo looked pretty good.  The next day, I took a sick day and headed to the local Electrical Power Plant, and it's nice and warm cooling lake.  Prepared for a long Break-in, I put in on the hot side of the lake and jus let it idle for a few minutes on the trailer. 

    The first 2 hours were spent between idle and 1/3 throttle (just enough to get up on plane), with 16 ounces of oil added to the 5 gallons of gas in the tank.  After pulling out for lunch, I returned for another hour and a half, again running approx. 50:1 gas mix. 

    To reach the 6 hour mark, it took another 3 trips to area lakes.  It was are real bummer to have my riding partners woopin my butt on my Yamaha.  But the tide will turn in just few more hours.

    Before hitting the lake after the 6 hour mark, I hooked up the flush kit, and ensured that the oil pump was working in the driveway.  Flexing the oil pump arm and pinching the oil line, I could see the oil refilling the line, thru the blue haze that should have told me it was putting out oil.

    Hours 6 thru 10 were spent cruising near 3/4 throttle with longer bursts to full.  This sure felt good, to open it up and finally leave my wife behind. 

    Now being Mid May '98, I am looking forward to a summer of liquid fun.