I bought my HiSUN 750 Sector about 2 years ago - have about 70 hours on it now. Use it for snowplowing my driveway (about 300' x 12') and 1/2 mile of trails in winter. I haul firewood on my 75ac and have also pulled logs with it. Had oil change and lube done at dealer at 50 hours and they replaced a missing exhaust flange. I don't abuse the machine i.e. no real off-roading through mud etc.
I joined this forum after I bought the HiSUN and was also worried when I read opinions here. (Luckily ?) no issues so far.
HiSUN Sector 750 Owner's Manual
This Owner’s / Operator’s manual will provide you information regarding safe operation, operational instructions, maintenance and care.
Good to know, hopefully that will help someone with the same symptoms in the future.
If you've got more issues or questions feel free to create a new post and we can try to help you thru any other issues.