Why does my scooter make whistling sound going uphill?

Check the speed control on the handle bar.

Take it in for service. It sounds like it has been modified or something is stuck in the motor fans.

We are Fixya, we aren't the maker of your unstated make and model scooter.

I moved the question for one of our mobility scooter Categories, purely as a guess!

hi Karin, normally because of the stress on the motor bearing that couples to the gearbox.. it 's a weak spot on many mobility scooters.

P.S Please rate my response as I have taken the effort to help you ..

Regards
Robin.

Make, model, year engine type????

Needs a check-up on the motor brushes.

hi Jennifer, well it to do with load,, ( in simple terms )the battery is under more stress when going uphill ,the controller is demanding more power to keep the speed up...everything is working harder to keep that speed up.. One trick is too simply slow down uphill to conserve battery power .... Going down hill there is no stress, only the motor slowing itself down , certain controllers can use this to recharge the batteries in a limited way ...commonly called regen

That is a real test to see how good your batteries really are ...

However please note : your batteries are only as good as your charger !!!!

Regards
Rob...

www.facebook.com/gewizrepairs

You maybe experiencing a brake hanging up, causing drag on the motor. the brain box senses over current use and will automatically slow down. The motor brushes maybe worn down and have a build up of carbon powder, particularly on the bottom side of the motor, causing this problem, remove brushes and blow out with compressed air, no Sprays please this can cause more harm than good. Note take out all brushes before blow it out with air. Check brushes springs are not discolored. http://www.strege.com/BlueDoc

I’m happy to assist further over the phone at https://www.6ya.com/expert/bill_bcbb89783b08c489

It's almost certainly a slightly binding brake, it often happens, especially if you have a sticky hand brake cable/ leaver. I've posted a full answer here as another Pride post.

mcdevito75 here, Sounds like the motor or clutch in the motor is giveing out, check with any Medical supply store in your area for repairs.

Hi. Does the machine do this more soon after removing the machine off the charger? When a mobility scooter is going down hill, the controller feeds the voltage generated by the motor back into the batteries. When I an testing machines here at the workshop, I have seen cases where 10 to 12 amps is going back into the batteries on a down hill run. If the batteries are fully charged or unable to take much current, the controller slows the scooter right down to limit the higher voltage generated.
It might pay to check the battery leads and connectors as well, and get the batteries tested.
While you are driving along, try moving the speed lever slowly up and down, not in and out as you normally use it. Sometimes a faulty speed pot ( wig wag ) will cause the speed to change.
Good luck. Neil.