What do I need to do to get higher volume of air at floor vents?

#1. make sure filter is clean
#2. nothing is blocking fresh air return
#3. if this don`t help maybe get a hvac tech to check fan speed

#4. if you have ac make sure evaporater coil is clesn

These are the most probable solutions offered by wmproop.

The only things I would add, and they go down in probability after his suggestions are.

5. low charge (low refrigerant) - a leak may be causing frost or ice on the evaporator coil blocking airflow

6. a leak in the supply side of the ductwork

For a duct leak check you can use the old door trick (http://phxheatpump.blogspot.com/)if the unit is blowing enough in the Mobile home.

I just assumed since it was the 2nd of March the your concern was when in the heat mode not in ac mode and problem could be in frozen a-coils,, sorry

You are right on wmproop. I am biased because I am in Phoenix and its almost 80 today. All I ever think about is staying cool..

Editor's Note: The OP, 'todays58', replied via email, and I wanted to update you guys:

Found out today that fan motor was a counter clock wise motor rather than clockwise motor. Turning in the wrong direction. Thank you

If it's a variable speed motor all cfm setups and adjustment are made at the thermostat and or control board. The make and model of your system will help.