Garage Door Opener - Last 4 Inches - Won't Open

Single Car - 8 foot door - not insulated

Garage door opener died ... trip to Home Depot ... got a replacement - 3/4 HPc - belt drive.

If I set the bottom limit to about 4 inches off of the ground, it will work every time.

If I set the bottom limit lower, it tries - then stops.

I have installed the track at the door about 2.5 inches from the highest point of the door.  The track at the opener is about 1 inch lower from the ceiling.

My old chain drive seemed to struggle also, but it could at least get the door up.  In truth there was always about an inch or two gap.  I recently adjusted the bottom limit to close completely.  Maybe that extra force did it in.

What adds to the frustration is that I think I've got it to close all the way.  Try it a few times - the world is good.  I go back 30 minutes later - it tries for about an inch - then stops.  Grrrr.

I have also tried varying angles of the elbow bar from near straight up to 45 degrees.

Some things I am going to try:

1. Lube the door wheels.
2. When the door is up, measure the distance of the track from the track bar to the top of the door and keep that distance at about 2 inches.  I may need to drop or raiser the opener accordingly.  I just used the existing setup from the prior garage door opener.
3. Figure out the force settings on the unit and see if I can't crank it up.

Any other tips and tricks?