Tools, Sharpening and Power Machinery - sears bandsaw problem

I got a 20" bandsaw second hand from a guy that got this problem , see it acts like either the blade is warped or something not adjusted right because it pops out of alignment and comes off.
I put it all back together and thought i had it adjusted right at the guides but with just a slight amount of pressure on the blade cutting something it will pop out.

any idea what is wrong and what i can do about it.
should i take it back to sears for repairs?

also what type of work is a bandsaw used for anyway.
I want something for building small projects and crafts ,should i buy a jig saw instead?

A band saw is used to cut curves in stock too thick for a jig saw. Cuts are more true on a band saw. A jig saw blade will bend and not make a true vertical cut.
Your problem sounds like the bearings in the blade pulleys are bad and letting the pulleys wobble which is throwing the blade off track.

You say it is a Sears 20" bandsaw? 20 inches is a LARGE bandsaw. Bandsaws are defined by the distance from the blade to the housing(how deep will it cut?). The upper wheel, I am presuming it is a 2 wheel bandsaw, has two adjustments. One to tighten the blade and the other to make it track right(not come off). The adj. on the top is to tighten blade. The one on the back is to adj. the angle of the top wheel to keep blade running true. Where the blade comes out of the housing, above the cutting area, there is an adjustment to lower the other 2 blade tracking devises. Cuts should be made with this adjustment as close to the wood as possible to keep the blade from wandering. In this up and down adjustment there is a ball bearing in the back that the blade touches when you make a cut. The bearing keeps it from wearing. There are usually 2 side adjustments in this same area that keeps the blade from wandering side to side. They should be adjusted so they just clear the blade. I forgot to say that the bearing behind should be close enough so that the teeth of the blade do not hit the side adjustment blocks. Don't get the blade too tight.
Put the blade on and rotate it by hand(power off) to see which way the blade is tracking. Adjust the top wheel adj. nut/bolt in or out to correct. Turn a couple of turns each time you adj. to make sure it is on track before powering up. Tighten jam nut if there is one. Hope this helps. A bandsaw is a GREAT thing to have but takes practice and patience. Blades come in different widths and teeth configurations. You can also buy a metat cutting blade. With each blade change, you will need to check/adjust the blade as described.

Ive never heard of a sears 20" bandsaw , they did a bunch of 12"

could also be the tires need replacement

Are we tightening the wheels tight enough to keep the blade on them? I go a fraction over the case marking to allow for stretch out.

My mistake I meant to say 10" .

I have tried over and over to get all those adjustmets correct but it still happens, I must be doing it wrong or like said bad bearings.

i'll try again before i throw it out the window,lol.