Stripped crank shaft

[AlSmythe]

I have a 200 Hp four stroke, 2002 with 1700 hours. Yesterday, without any warning signs, vibration, etc., the crankshaft stripped out from the drive shaft. The drive shaft looks perfect. The motor has been meticulously kept and still bears original paint on the skeg. It occurred just after backing off the trailer and placing the engine in clutch ahead to pull to the dock. What happened? This is a costly repair as to the entire crank shaft must be replaced.

Al Smythe

[boats.net]

Had some become stuck due to lack of grease on splines but haven't seen any stripped.

[robert graham]

Did you find all those splines that came down out of the crankshaft? That's a new one on me, but if the splines are in fact stripped out, and the crankshaft requires replacement, it'll be expensive$$$

[AlSmythe]

yes they all came out. I havent had anyone hear of this yet. I would not have been taking out the boat if there were any signs of problems. I should be thankful it happened in the boat basin.

[robert graham]

Since the motor is 10 years old, but in otherwise good shape, then take it to a Yamaha dealer for a quote to replace the crankshaft, or install a rebuilt or remanufactured powerhead. Failed crank splines has to be a rare occurence!
Sorry for your trouble and good luck!