ACR J10 gears slipping

Hey guys I’m new to the gel blaster world and iv been really enjoying it!
So iv got a ACR J10 Jim Ming. Straight away I upgraded the seal, spring and barrel. After doing all of this it worked good for about 10 mins then it shopped shooting and makes a grinding sound. As if the motor gear isn’t in the right position or some gear isn’t quite right and slipping? Anyone have any ideas?

Difficult to say without more info.
Before taking anything apart, try using the stock spring.

sounds like what my Gen 9 did… The pinion had knocked over the teeth on the first gear, so the pinion couldn’t get a grip… Try moving the gears by hand so the pinion can grip some teeth…

Did you use a 3S battery?

1 Like

Yeah I was using the 3S battery. Sorry I don’t really know all the names yet. But I got a new plate that holds the motor in and it’s adjustable hoping that might fix it, so I could adjust the height that the motor sits but it still seems to do it

Iv thought about trying the stock spring. Might have to give that a go!
What other info would you like?

What size spring did you use?
Grinding noise could mean several things in the ACR.
Any of the gears could have lost some teeth.
The pinion gear (on the motor) could have stripped.
The ladder could have lost its lead tooth.

If it works a little with the stock spring, it’s likely that there is some pinion gear stripping and the motor is just being pushed back.

If it still doesn’t work then it’s one of the other gears or the piston ladder.

I put a Ausgel 1.18 spring in
So it might be best to try the stock spring and if it’s still doing it pull the box apart and check all the gears?

Better get used to it.
While you’re at it, also check that the pinion gear hasn’t come loose and slid closer to the motor. Sometimes that needs shimming as well. :sunglasses:

Hahaha these things can be quite fiddly but pulling it apart for the 4th time might be even easier :joy:
It is possible that the spring pressure is to “stiff” that when the motor tries to turn on the gears the motor moves a bit so it’s off centre? Because I feel as if where the motor sits it’s quite loose in there?

It should be a little loose unless your new motor plate is vastly different from stock.

The 1.18 spring should be fine, not overly big.
I use 1.3 equivalent in both acr’s…
I suspect you got a gear mesh problem, but I could be too late and the damage done.
I’d start by pulling out the motor and checking the pinion gear, if looks ok look down the grip to see if you can see the bevel gear for damage! But more than likely you’ll be stripping apart again I suspect.
J10 nylon gears in my opinion are quite sturdy.
But you can get a metal set for bugger all if you need too.


Do yourself a favor and order some metal gears if you want to use 3S… You will need them

It has been my experience that the nylon gears in Gen 9 and J10 can handle a 1.3mm spring on 2S… but tend to strip the 1st gear where the pinion engages… when doing alot of single fire, the gear always tends to sit at the same place with the pinion (because of the anti reverser thingy)… the teeth don’t break off… they just lean over and the pinion spins against the leaned over teeth and just makes a whining noise…badluck

The rest of the teeth on the first gear are still perfect killbunny


Hey guys just an update!
Thank you for all the help, it’s much appreciated. And such a good group to be apart of with everyone helping each other!
So I pulled the motor cover off and checked the pinion gear it all looked fine, and the side gear on the bottom of the gear box it also looked all good. So I put the moto back in but left the cover off and held the motor in with my finger and pulled the trigger. It worked for a couple of shots then the motor moved a lot and started doing that sound again. So I made up some shims to go down all four side of the motor to make it sit tighter and more in the centre. Tried that with holding it with my finger again and it worked fine. So I put the cover back on and I haven’t had a problem yet!
So hopefully that’s the end of that issue. Or “for now” :joy:


Arrrr yes, you might have to swap the motor shaft sleeve thingy over, the stock one fit best in mine. The new one looks better but she no fit!!
Oh yeah and check the spring on the motor shaft the new one was also too long! :man_facepalming:t2: