Small Engines (Lawn Mowers, etc.): Craftsman Lawn Tractor wont drive FWD/REV, craftsman lawn tractor, woodruff key

Question
Dear Marc,

I have a Craftsman Lawn Tractor model 917.270722  17HP electric start 42" mower automatic, which I am having all sorts of trouble with.  We are not the original owners and we can tell it was not taken care of or maintained properly previously.  We got it for a trade and have been using it with little troubles for the last year and a half.  In the fall we had the flywheel, starter, and blade replaced. It wouldn't start unless I manually turned the flywheel (one of the little troubles).  Then we replaced the mower blade drive belt (broken), battery, airfilter, fuel line, fuel filter, and sparkplug because a month later it would not start.  We tested the spark plug and bypassed the seleniod, it still wouldn't turn over.  I cleaned and checked all contacts and wiped everything down and it still wouldn't start.  We are using fresh gas and the oil has been changed. Well a miracle happened, it finally started and I did 3 swipes on the lawn and I was happy, however I noticed it wasn't driving nearly as fast as it usually does.  I put it up for later and yesterday I went to get back on it and now it will not drive forward or backward.  It starts but when I move the lever from N to FWD or REV it goes no where.  The blade engages fine and the the freewheel control knob is set correctly.  I am going nuts over this.  Can you please help?

Thank you :)

Michelle

Answer
The first thing you want to verify is the drive belt assembly from the engine to the transmission.  Any misadjustment of the idlers, clutch, etc. can cause the belt to slip and not properly drive the transmission.  Another thing I've seen happen is the woodruff key in the driven (input) pulley of the transmission sheared.  If the belt is tight and not slipping, the problem may be in the linkage from the control lever to the transmission.  If you can eliminate everything external that either drives or controls the transmission the problem could be internal.  Let me know what you find and I'll try to help further.