The belt keeps coming off and does not sit straight on the wheel

look at the other pulleys is the belt going on straight to the harmonic balancer or is it on an angle one of the other pulleys may be bad check them all

I'm guessing there's no bracket around the pulley itself, you can rig it just drill a hole close to the pulley straight down to the deck and put a long bolt to sit beside it, you can put 2 of them on there one on each side, but if there was never one there in the first place odds are your deck belt is stretched replace it, hope this helps

If the belt is coming off the pullies my be out of line .you need to put a straight edge across the two pullies to make sure they are level . And check there's enough tension on the belt .

First thing that comes to mind, check steering fluid and belt condition, as well as tension on belt.

on the front wheel , there is a screw that you can adjust ,, that will adjust the tracking of the front wheel, the rear wheel is stationary , once you have the new belt on, locate that screw,, and just click the switch as you adjust it,, once adjusted, you will see that it tracks straight and won't fall off

a bad idler arm/pitman arm, You will have a hard time trying to keep the car going straight, it will wander all over the road.

1. Road walking. When the vehicle wanders back and forth in the direction of travel and it is difficult to keep it straight.
2. When sitting still, there is considerable play in the steering wheel. It can be moved considerably with no resistance.
3. When sitting still, and with the front wheels off the ground, it is possible to move the wheels side to side without the steering wheel moving. If there is to much play in the steering wheel or side to side movement of the wheel when the vehicle is stopped could indicate there is a problem with the idler arm.

Either the belt is over-tightened or there's a chip/nick on one of the flywheels. Check the pullies that the belt passes over. If there's a nick use a fine file to smooth it out. Also, make sure the pullies line up so belt runs straight. The belt needs to sit in the concave.

FOLLOW THE BELT, IT WILL GO AROUND SEVERAL PUMP PULLIES ANS SOMEWHERE ALONG THE PATH YOULL COME ACROSS A "BELT TENSIONOR" IT'S A SMALL WHEEL ABOUT 1.5 T0 2.5 INCHES ACROSS. FEEL FOR A BOLT HEAD IN THE CENTER OF THE WHEEL. FIND A SOCKET THAT FITE AND WITH A STRAIGHT BAR OR RATCHETT ATTACHED TURN THE BOLT IN THE DIRECTION THAT WILL LOOSEN THE TENSION OFF OF THE BELT THE TENSIONOR IS A SPRING LOADED DIVICE THAT AKES UP SLACK IN THE BELT AND KEEPS IT TIGHT.

I think that's easy to find online. Very common mower. Here's a link to Amazon and Murray belts

Amazon com lawn mower belts murray 46

This is the same problem I had. We took it to a vacuum repair store and they fixed it for $80.00!! It lasted about 6 months and it just happened again. I'm not spending the money - I'm looking for another vacuum cleaner.