Rear hub motor only spins when it's upside down

Morning all, I dug out a spare 3000w motor I had lying around but it will not move when it's on its wheels but spins as expected when the bike is upside down, we'll technically it does move but only a cm or two and then jerks back to where it started.

I'm running it sensorless and I've checked all of the internals, also the cable where it pops out of the axle, and all connectors. Everything is fine, and there's no hall sensors to connect to the controller, to test because it's how it came to me from a friend.

Any ideas guys, in my limited experience my mind is leading me towards the controller maybe?

My son once had a puppy like that. When on its back he would paddle frenetically with all 4 legs, but when on its feet you had to pull him on locked brakes.

Sometimes a sensorless controller will need a nudge, try right side up, and apply throttle while the wheel is slowly moving forward. It might work, but backward. If nothing, your problem is the usual one, a bad connection that looks good. Or more rarely, the controller won't work in sensor less mode. Or never could.

Do other motors work with this controller?

I've tried the nudge and it didn't make a difference mate, and no mate, it's the same on 2 motors. My guess is the sensorless mode, because at least a few times I'm gone through the sequence and when I go to ride away it has gone into reverse. And my god the first time it was a shock to my ball, not a nice feeling. Lol. After that I got into the habit of making sure the back wheel was against a wall.

Luckily enough the new kit that I ordered arrived 5 days early, so it's more of a " I will fix you" thing rather than a necessity. I'm my 92 year old grandfather's primary care giver and my bike is probably the most important thing in my life that I own. He lives 6 miles away and iz my only form of transport, the last few days have been awful without it so I'm so glad that I've got a new one, I'm just about to get it fitted.

Sensorless controllers are sometimes a bit tricky. Some are pedal first, meaning the wheel has to start moving before you apply throttle. Some have a learning mode, and need to be set by slowly moving the wheel forward while the learning mode is active. Then you remove the learning mode and it does remember the forward sequence. Instructions should tell you, but sometimes instructions are in Chinese language only, and sometimes there aren't any.