Burst fire on 11v

Just upgrade the battery to an 11v Lipo and now in Semi-Auto I get a two round burst

it could be the semi cutoff not resetting in time due to a number of reasons, all related to inertia in the system which only becomes a problem at high cyclic rates. Fixing this probably requires a complete teardown of the gearbox. Here are the things that I did to a blaster that had the problem, and now doesn’t:

  1. reduced the mass in the tappet/nozzle assembly by changing a brass nozzle for aluminium (probably not the cause)

  2. changed the gearing ratio, thus also replacing the worn pin that actuates the cutoff

  3. reseated the cutoff with a new screw so it only rotated and didn’t wobble side to side in the gearbox (I think this is the biggest contributor to the problem in my box)

  4. changed the motor, reducing the cyclic rate slightly

Sorry I can’t be more help, but in the first instance I’d check your cutoff lever is not wobbly, and if it has become wobbly check it can move freely (lubrication!) so it doesn’t bind and become wobbly again!

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Its all standard, and only a few weeks old
I have a spring and o-ring on order, so might go back to 7.4v until they arrive then see what happens

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IMO you have to build around 11.1v if you want semi auto with blasters that run the trigger system on the trolley with cut off lever. Specially if you use higher quality batteries with higher C ratings

  1. you will likely get arcing on trigger terminals so they will start sticking.
    2.motor keeps going after releasing trigger.

Ways to build for it include
Mosfet to prevent arcing of trigger terminals and get semi auto functioning
*With non active brake mosfet (easyfet2 $20) use a rare earth magnet motor so slows quicker. Also a slightly stronger spring can help by creating more resistance to motor to slow quicker.
*Active brake mosfet (perun ab $50) really recommended if wanna keep most parts stock. This can make your motor heat up a little quicker.
For such simple toys they can be a pain in the arse.
All the above is from my experience and watching videos, others experience may vary.

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a little grease on the trigger contacts prevents arcing too.

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SOLVED
I fitted a M90 spring and a green O-ring and the double shot has vanished
I assume the added load of the spring slowed things down enough to stop the second fire

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I’ve got the same problem, also occasionally while in semi, it somehow slips back to safety and i have to switch to full auto then back to semi to get it to fire again. I can’t work out why.

I solved the issue with the spring and o-ring

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