I have a craftman rider that I changed the belt and blades and it won't cut. Blades slows or stops when high grass is met. Doesn't sound like it used to. Any idea from someone with more knowledge than me.

Heck my new cub will stop if I hit tall grass too.. what are we talking about.. 2 feet or higher?
When you say it doesn't sound like it use to are you talking about just the engine or the combo of deck cutting grass and engine?.

Engine may just need its oil changed out... heard that quiets the engine almost all of the time

The deck might be plugged up with old grass... so it has nowhere to escape...

Deck height might be too low

Might be trying to cut too much at once...

Driving too fast.. might need to go slower

Tune up might be in order... plug(s).oil filter,air cleaner.oil

That's off the top of my head for now.. but if I can think of anything more I'll get back to this...
Or
Worse case scenario the compression on the motor isn't there anymore... might need a new motor

Good luck

I don't think it's the oil or compression, But pretty much its all true... try going slower, clean the deck from underneath. Are the blades sharp? Sharpen them if not.

I guess I should have said the blades slow or stop when I hit grass about six inches high. Also, when I engaged the deck the sound doesn't get louder as it use to when I did it before. I cleaned everything and went slower and even cut higher but no luck. Thanks for input.

Ahh, check the belt, it could be worn out. They will from all the engaging and disengaging. And also the whole pivot system, they can get stuck with grass and such. Don't oil them, that will collect dirt but use a graphite powder and the like.

Thanks BM the belt was new maybe I burned it out it was smokimg a little

Take a look at the deck, and the belt. There should be little keepers around the pulleys, its not impossible that the belt was put on the outside of one or two, and smoked the belt.

a) Maybe want to check to see if the bearing on top of the deck. One could be bad.
b) Belt could be slipping due to wrong size. If you buy a belt from an electrical motor repair place there is enough differnece to not work or last long.
c) Check blade(s) were mounted in the correct direction cutting clockwise
d) See if tractor rides and does not bog down just on clear area with deck raised and then with blades engaged.
e) These are my thoughts. Might help in narrowing down the problem(s)

Anyway... Good Solution will show up soon. Sometimes it helps if you have a friend with a fresh insight and can actually see the equipment.

Raise your deck for a 4" cut. Sell if that works. It will pan out.