First look up the jack you have on it's company website—maybe, just maybe, the warranty is still in effect. Then see if you can replace the gears, manual handle and anything else you need. If you have an Equalizer WD hitch, you should have a lever to put the bars on and take them off so you don't have to raise the jack as much. The lever is a bar with a hook like end.
On a hot day the fuse is more likely to blow. If you raise and lower the jack a lot, or reverse direction before it stops, the fuse is more likely to blow. The closer you get to maximum extension, the more likely the fuse is to blow. Do all those things at once, even more likely.
You can probably get a higher capacity jack, but try to fix the one you've got first.