so i had a pretty rough landing last week, clipped a tree branch on the way down and the quad hit the ground on the front right arm. props were trashed obviously but i replaced those and now when i spin up that motor it stutters and kind of hesitates before getting up to speed. the other three spin up clean.

ive swapped props around to rule that out. same thing. the motor itself doesnt feel rough when i spin it by hand, bearings seem fine, no grinding. but under power it just doesnt behave right. im running 35A BLHeli_32 ESCs on each arm individually so its not like a 4in1 situation where id expect more crosstalk issues.

my question is basically how do i figure out if its the motor or the ESC without just buying both and swapping them out. i already checked the motor screws and they're all tight, checked the solder joints on the ESC too and nothing looks cold or cracked. is there a way to test this more systematically or am i just gonna have to swap one and see

plug the suspect ESC into one of the arms you know is working and test that motor with it. if it still stutters its the ESC, if it clears up then the motor is your problem. takes maybe 10 minutes if you dont have to resolder anything. you could also do it the other way and put a known good ESC on the suspect motor but i find it easier to move the ESC around since the signal wires are usually easier to swap out on a bench.

also worth checking the ESC firmware didnt get corrupted somehow, ive seen that happen after a hard impact. reflash it with BLHeliSuite before you go buying anything, takes two minutes and might save you money.

had almost the exact same thing happen to me with a 2306 after i faceplanted into gravel. turned out to be a bent motor shaft that was just barely bent, like you couldnt even really see it until you spun it up and watched the prop wobble slightly under load. might be worth pulling the prop off and looking straight down the shaft while someone else spins it up slowly, even a tiny bend can cause that kind of behavior