Small Engines (Lawn Mowers, etc.): Engine gets extremely loud and high when engaged, mtd lawn tractor, main bearing

Question
I have an MTD lawn tractor that is about 3 yrs old.  The model number is 13BI675H062.  This season, when I would engage the blades it would sound like the engine was going to explode with an extremely loud high pitched sound.  I bought new blades thinking that was the problem because my old ones were very worn.  It still does the same thing.  It runs fine and sounds normal until you engage the blades.  The blades are turning and will cut the grass great but I'm afraid I'm going to blow the engine the way that it sounds.  What should I do?  Please explain in as simple terms as you can as I'm a woman and not very mechanical inclined.  Thanks for your help.

Georgia Ballard

Answer
Hi Georgia
Somewhere, you have a bearing that is going bad (or already is).  I hope its on the mower deck and not in your engine.  Do this test, crank it, let it sit and run at idle for 10 solid minutes.  Put it in hi gear, drive it and run the throttle suddenly all the way up and down several times.  Does it squeal during this test?  If so- you're engine needs rebuilding (lower main bearing for the crankshaft is going bad).  If not, you're mower deck has a blade spindle with a bad bearing (this is much more likely).  Have a reputable shop replace it for you (and get a new mower-deck drive belt while you're at it)
* - one other possibility- your deck has a brake system.  If the brake lining is gone, and the release arm is worn or bent, the bare metal brake arm will make alot of noise- but this is also a deck problem and easily repaired.
Lemme know K ?