version 6 tappet plate.

i have an echo one p90. the p90 doesn't always fire at its full fps. i took it apart yesterday, and im wondering should the tappet plate be really flexible. and could that be causing my miss-fires. also its not shimmed correctly so im also wondering if that may be causing the problem.

Not shimmed correctly won't effect feeding and the tappet plate is suppose to be flexible.

when dry firing the nozzle doesn't always retract fully and it doesn't load the bb during that shot. do you know what could be causing the miss fires?

Does the tappet plate look worn at the spot where it's engaged by the sector gear?

Ryan, what if the sector gear is shimmed way too low, could that affect feeding?

Admin wrote:Does the tappet plate look worn at the spot where it's engaged by the sector gear?

Ryan, what if the sector gear is shimmed way too low, could that affect feeding?

it doesn't look worn but like i said it feels like it flexes more than it should.

Admin wrote:Does the tappet plate look worn at the spot where it's engaged by the sector gear?

Ryan, what if the sector gear is shimmed way too low, could that affect feeding?

no

sniper2525 wrote:

Admin wrote:Does the tappet plate look worn at the spot where it's engaged by the sector gear?

Ryan, what if the sector gear is shimmed way too low, could that affect feeding?

no

then what could be causing the miss fire?

after a shot, the nozzle doesn't always retract all the way. when it cycles, the sector gear will retract the tappet plate for bb loading. after it releases, it will stop where ever it wants. sometimes retracted, sometimes not retracted at all.

fps loss is usually caused by leaky air nozzles. mine leaks after it reaches 500 fps. putting a tighter fitting o-ring metal nozzle has too much drag and causes jams at 40 rps. guarder o-ring nozzle works great. king arms tappet plate are off spec. i had to trim it to fit guarder nozzles. guarder tappet plate is stiffer and stronger than the clear stock tappet plate.

with the tappet plate spring removed, the tappet plate should slide forward and back without any resistance. if there is any drag, it will cause feeding issues. don't use lube on it. i usually sand down the sides so the plate moves much easier and quicker.

springs will lose their original fps after time. my 420fps m120 spring dropped down to 380fps after 50k rounds. this was tested by putting in a new m120 spring and it chrono'd back to 417 fps.

piston to cylinder compression can take abuse. even a bit dry and dirty, it will still hold compression. it either works or it doesn't.

hopup may sometimes cause air leaks (fps loss) but this happens with high fps springs.

misfeeds generally occurs with bad mags or worn out tappet plate. the part that contacts the sector gear will eventually wear.
also, a misaligned or torn hopup bucking may cause feeding issues.

the shimming should not be tight. with just the gears in the case, screw down the case (minus motor) and spin the gears. it should spin easily, making a complete cycle. if it's too tight, it will stress and overheat the motor, sometimes causing gears to fail.

i dont think its leaking because every couple of shots are really hard and the next few just fall about 15' away.

does it shoot fine on semi auto or during full auto?
also, are you using the mag that came with it or hicaps?

-a|ex wrote:does it shoot fine on semi auto or during full auto?
also, are you using the mag that came with it or hicaps?

in both. and im using a hicap mag

use the 68 rnd midcap that came with it. see if it still does that. all my hicaps misfeeds. i ended up getting an m4 boxmag adapter.

-a|ex wrote:use the 68 rnd midcap that came with it. see if it still does that. all my hicaps misfeeds. i ended up getting an m4 boxmag adapter.

its not the mag its feeding rounds correctly, but its not firing them fast enough it always launches a round but most of them land about 15-20' away while some of them fly like they are supposed to.

if it feeds correctly then it's most likely a random air leak. usually nozzle to bucking. replace it with a mad bull blue and be sure to align it. it is usually a tight fit and takes several attempts to seat it in correctly.

as i mentioned earlier, my hicaps have a high spring pressure which causes the nozzle to leak during semi auto, but works fine on full auto. it's not a misfeed, the bb's feed fine but drop around 15-20 feet on semi auto only. when it drops in full auto, it's usually from the tappet plate binding. if it's not shimmed correctly, the sector gear may rub too tightly against the tappet plate. this usually isn't the case unless the tappet spring too weak.

have you tried sanding the sides of the tappet plate so it moves more freely?

if you have done any upgrades, please post them up.

-a|ex wrote:if it feeds correctly then it's most likely a random air leak. usually nozzle to bucking. replace it with a mad bull blue and be sure to align it. it is usually a tight fit and takes several attempts to seat it in correctly.

as i mentioned earlier, my hicaps have a high spring pressure which causes the nozzle to leak during semi auto, but works fine on full auto. it's not a misfeed, the bb's feed fine but drop around 15-20 feet on semi auto only. when it drops in full auto, it's usually from the tappet plate binding.

have you tried sanding the sides of the tappet plate so it moves more freely?

if you have done any upgrades, please post them up.

havent sanded the tappet plate and there are no upgrades to the mechbox that i know of i bought this used so im just trying to get it working.

mwilson wrote:
havent sanded the tappet plate and there are no upgrades to the mechbox that i know of i bought this used so im just trying to get it working.

only sand it down if it's binding with the gearbox.
if you can't resolve it, send it down to airdog or sell it to me for what you paid for it. i can always use another for parts.

-a|ex wrote:

mwilson wrote:
havent sanded the tappet plate and there are no upgrades to the mechbox that i know of i bought this used so im just trying to get it working.

only sand it down if it's binding with the gearbox.
if you can't resolve it, send it down to airdog or sell it to me for what you paid for it. i can always use another for parts.

how easily should it move?

heres the tappet plate let me know it you think i should replace it

[img][/img]

yea pic didnt post

it could be that your gb is not meeting with the body correctly. Make sure you have both of the rear plate screws fastened correctly

and i just checked it there is about a 1/16" of play side to side in the gear that engages the motor and the gear that engages the piston.

the side to side movement in the gears must be checked with the gearbox screwed together or you will get false measurements.
picture of the tappet plate won't tell if it's binding in the gearbox. you can tell how tight it is by removing the tappet plate spring and moving the nozzle (attached to the tappet plate) in and out. there should not be any drag. make sure the sector gear isn't interfering.

have you tried removing the bucking, cleaning it with soap and re-inserting it?

-a|ex wrote:the side to side movement in the gears must be checked with the gearbox screwed together or you will get false measurements.
picture of the tappet plate won't tell if it's binding in the gearbox. you can tell how tight it is by removing the tappet plate spring and moving the nozzle (attached to the tappet plate) in and out. there should not be any drag. make sure the sector gear isn't interfering.

have you tried removing the bucking, cleaning it with soap and re-inserting it?

the picture was if you could see if it was worn down. and i did move the nozzle with out the spring and it could be smoother but its not too bad. and that measurement was with it screwed together.

the gear shimming shouldn't affect air seal (cause of the bb's dropping). for me, it's hard to instruct someone how to properly shim the gears correctly online. you will need a shim kit (assortment of shims). 1/16th side to side movement is too much play but as i mentioned, doesn't directly affect air seal.

i didn't expect to see any wear on the tappet plate, a worn out tappet plate will prevent bb's from loading.

when you took the front receiver apart, there should be a spring behind the hopup. if that is missing you won't have a good seal between the hopup and the gearbox. check if that spring is there. it looks like a very large motor shaft spring.