My husqvarna tractor is slowing/stopping completely when going up hills. What's causing the problem?

you have unseated valves the hotter it gets the less power you have until it stops to cool down need to take to shop and get vavle job about 100.00 dollars if you wait you will damage motor

sounds like your transmission is going bad fast. get it checked asap to see if it can still be saved. aamco will take a look at it. if its completely bad, then getting a new transmission might be cheaper than getting the current one fixed so look into that!!

i will try to help... is it a hydro or geared hydro has a release on the back of the rider if the fluid is low then this can slip kick and make it seem like the trans axle is going out if its geared then they could be rounded off and causing you to stop slowly and not pull a hill

Some self-propelled mowers include a speed control, but sometimes it may seem that no matter how you adjust it, the mower just creeps along at a snail's pace. Most likely this isn't a mechanical malfunction, but an adjustment is probably needed.

Very tall or thick grass can bog down a self-propelled mower, but adjusting the height of the blade may allow it to roll through and cut the grass at normal speeds. If the blade is low, the amount of cutting required may slow down the movement of the entire mower. The frame of the mower may also stick in the high grass. Raise the blade little by little until the mower rolls at the appropriate speed. Going up hills may cause a similar response.

It's possible the drive belt on the mower can slip. Inspect this part to see if it is loose or cracked, and replace the belt to restore power.

for not charging pull the cover off the top of the engine look for damaged wires mice love to eat them going slow i would check the belt for oil or see if its tight

either your drive belt is loose/stretched or your transmission is going out. check the belt and tensioner.

if the engine is running well, sounds like your hydrostatic transmission is going out.

It is likely that your transaxle just isn't up to the task. I suggest that you try to operate the machine on the hills prior to going on flat land. This is a huge problem with these machines.

Same reason a person slows down when he is riding a bicycle up a hill?
Does the engine nearly die when you engage the blades on the fly?
If so you may have a dead cylinder, my 2148 would mow on the flat pretty well but not an incline with one cylinder. Cause of my dead cylinder was bent pushrods, which is not unusual on V-Twin B&S. You can test this by pulling one spark plug wire off at a time and running it.