The rear tire is flat, how do I inflate it? - Troy Bilt Walk Behind Chipper/Shredder/Vacuum 205cc

If the tire is not damaged and will hold air then you may be able to reseat the tire. One method if you do not have proper tools or do not want to go to a tire shop is to lubricate the sine of rim with a dish soap solution to make it slippery. Take a ratchet holddown strap and run it around the tire and tighten it to force the beads of the tire onto the rim. Then use a compressor to inflate the tire and the beads should snap back onto the rim. Once that is done, remove the strap, remount the tire on the tractor and inflate to the proper level.

First turn the adjuster on the rear brake handle all the way in and make sure the slots on the adjuster and set nut are lined up, pull the brake cable out and leave it attached to the lever to open the rear brake pads, loosen the bolts on the tire and pull the derailer up to remove the tire, remove the dustcap from tube and using a flat tool (Wal-Mart has tire tools for $1) take one side of the tire bead out of the rim, pull the old tube out, place the stem of the new tube in the hole and put the cap on, tuck the new tube in the tire trying to keep it flat as possible, push the bead of the tire back into the rim. before inflating the tire, put it back on the frame while pulling the derailer up to get the chain back on the cogs( they will adjust later) tighten the bolts and inflate the tire to desired pressure (between 35-60 psi)

Jack the car up on the side you want to inflate to get the weight off of it. No compressor that i know of that plugs into a cigarette lighter is strong enough to inflate a flat tire under that much weight.

From the Clymer

TIRE INFLATION PRESSURE (COLD)
Front 28 rear 32 add 4 for riding double(from the Clymer manual).

Tire inflation pressure for factory equipped tires. Aftermarket tires may require different inflation pressure.

put the jack right under your passenger side door

Your tire tubes may have been replaced with urethane foam inserts - these give a comfortable ride like air-filled tires but cannot go flat - would explain why you don't see a fill valve - these inserts fit inside the regular tire carcass.
If they are worn out, you'll need to replace them, process is same as replacing a tube.

It either has Tire Pressure Monitor (TPM), or Flat Tire Monitor (FTM)

TPM:Checks the tire inflation pressure in the four mounted tires. The system indicates if the tire inflation pressure has dropped considerably in one or several tires.

FTM:Keeps track of the inflation pressures in the four mounted tires as you drive. The system triggers an alert whenever the inflation pressure drops significantly in relation to the pressure in another tire.

Most electric mobility scooters with inflatable tires require a tire pressure of 30-35 psi (be sure to check the manual of your scooter for the correct tire pressure). Do not allow the tires to become under-inflated or over-inflated. Under-inflated tires could make the scooter unstable and over-inflated tires can burst under pressure. Also, you should manually inspect the tires periodically to make sure they haven't taken any serious damage that could lead to a flat.

32 to 35 PSI

I don't think you have an MPV4. That model has 2 rear caster tires that are solid and require no inflation. The front drive tires have a valve stem sticking out of the center rim that is easily accessible. Make sure your power chair is gray and says Hoveround on it.