Clean the Chute with soap and water and let it dry completely.
The use a spray with a very high concentration of SILICON Lubricant and Completely coat the inside of the chute with it..
All we really have left is to reduce the friction as much as we can. If we can stop the grass from lodging just a little bit, then we can also slow the clogging process.
Lastly, Overfill the tires with air just a little bit.
If you put more air in the tires, you will raise the cutting height nearly an inch. This will help to increase airflow and give your better bagging.
Higher is better. You should never take more than 1/3 of the hight of the grass off at one time. So if the grass is 4 inches long, I would cut at 3 inches...
Leaves need Higher cutting. You want to pick up the leaves without cutting much grass.
Have a technician adust the ENGINE RPM to be 3500 RPM.. Very possibly, when you purchased it, it may have not been professionally set up.
Have them use a digital tachometer and set it exactly..
This will give you the highest blade tip speed allowed by law.
Have them perfectly level the mower deck from side to side and then have them make the mower deck more level from front to back.
Have them make the front of the deck be ONLY 1/8 of an inch lower than the back of the deck..
When these get older the front tends to dip and droop because of the wearing of all the hardware. This takes away all your suction..
These MTD units are not of the BEST design available. They have a reputation for not doing a good job of bagging at all. BUT, I hope that I have given you all the best hints.