Small Engines (Lawn Mowers, etc.): MTD 1994 L667 Series Mower question, spindle bearings, blade of grass

Question
QUESTION: Hello

The mower is a 2 blade 38" cut 1994 version MTD series 667. Problem I have had the past few weeks is the right blade doesnt seem to be cutting very well...both blades are new and installed the same way the old ones were installed.

Troubleshooting...

With the mower off, blades in the disengage position, the left blade will not spin freely. The right blade will spend around and around by just a small hand movement.

Is the Blade Spindle assy bearings shot and need to be replaced? Trying to understand why the right blade all of a sudden will spin around and around but the left blade doesnt.

Thanks

MTD 134-L667-F118

ANSWER: There could be a brake on the left spindle. This is to stop the blades quickly.  If you wan to inspect the spindle bearings the beat thing to do to start is remove the belt from the blade spindles.  Then check for wear in the bearings.  Carefully grab the blade at the end and see if you can move it up and down.  You are checking for excessive movement in the spindle bearing.  If so replace the assembly, they are not rebuildable, I think.  

Did the quality of cut problem start after you replaced the blades?  Did you hit something with the right blade?  The reason I am asking is that if you did you may have sheared the key in the pulley or blade adaptor.  The thing that holds the blade to the shaft.  Check this too.

If blade replacement was to correct poor quality of cut be sure you have the correct blades, not will-fit.  

Next, have conditions changed?  If the grass is heavier slow down.  Clean out under the deck more often.  Mow the grass at a regular interval.  Meaning mow weekly not letting the grass grow really and then cut it short.  Keep it the same. If you are mowing at 3" let the grass grow 1.5" and then mow it to 3".  Use the 1/3rd rule.  Never cut off more than 1/3rd of the blade of grass at one time.  

Pull out a blade of grass and look at it.  See where the white begins?  DON'T mow it that short.  The grass should still be green after you mow it. Let me know how you come out.

---------- FOLLOW-UP ----------

QUESTION: Thanks for all your information. I did check the blade and I cannot move it up and down...pretty solid. The quality of cut happened a few months after I changed the blades. Both blades cut great then all of a sudden the right side was not cutting very good. Both blades are sharp and both blades are the correct ones for the mover. I did not hit anything either. I did check the blade adapter and it appears fine.

Mowing conditions have stayed the same for the most part.

Still stumped...just don't know why the right blade can spin around and around with a little push while the left blade wont budge doing the same thing to it.

Thanks for your help

Answer
Is there a manual PTO or an electric clutch?  

If a manual clutch engage the blades, so the belt around the blades is tight.  Can you still turn the RH blade freely?  If so remove the deck and inspect the blade, blade bolt, adapter, pulley, spindle bolt or nut, etc.  If you don't see anything remove the spindle and inspect the pulley. You should find the problem.  If electric clutch the belt should be tight all the time. Follow the same instructions.