22 replies to this topic

[alpha5398]

When i shoot my p90 in semi it will shoot fine, but when i shoot in full auto it will shoot but when i stop shooting and try to shoot again the gun will lock up. Any help would be great. thanks

[Merana]

If I had to guess you're either running into a feed-jam problem or a gearbox issue. Knowing a bit more about your setup would help a lot.
A few details that would be handy in troubleshooting:
Who's the manufacturer of your gun?
Is it stock, or have you had modifications done? If so, what are they?
Are you using a higher voltage battery than the stock one?
What weight BB's are you using?
Lowcap or Highcap magazine?

**DISCLAMER**
Keep in mind that I'm just an educated player, and not an airsmith. If you have even the slightest worry about opening up your gun to perform repairs, bring it to one of the friendly airsmiths at The Citadel and they'll help you out. Better to spend $ having a pro fix your gun than to botch your own repairs and have to spend $$$ replacing your entire rig.

[alpha5398]

The Gun is a Echo1.
Internals:
everything is sock execpt the gears are shs 13:1
I use .20 bb's
The gun shoots and feeds fine
its a p90 box mag
using a 9.6 1600mah battery (Same as stock)

I just ordered a m90 spring to see if that could fix it (cqb gun so idc about fps)

[jwberry]

My best guess would be that the combination of speed gearing, stock motor, and 9.6 battery has trouble pulling a precompressed spring from a dead stop. You can test this theory if you get it locked up then put a 11.1 lipo to see if it over comes it. A lighter spring would help, as would a high torque motor. A 11.1 lipo would also help but just lead to trouble unless you upgraded other parts.

[alpha5398]

I already ordered a m90 spring. (it's a cqb gun) I also ordered some deans. Im getting a bigger 9.6 in a while. If that all fails im going to get a shs HT motor. Not ready to dump alot of money into lip stuff yet. (mosfet,charger, lipo, and parts they break)

[mhealey]

Ya i agree with jwberry. i dont think its a big issue, it should be fine with the new spring and battery

[alpha5398]

just put in a m90 spring and it works perfect!! no more lockup!!

[mhealey]

That's good. What kind of rof are you getting with the stock motor?

[alpha5398]

ran it through audacity and was getting around 20rps
internals:
shs 13:1 gears
stock E1 motor
m90 spring
9.6 1200mah with deans
stock piston
random ported polycarb piston head
stock cylcinder
stock tappet/nozzle
stock spring guide
reshimed to bevel
regreased

i justordered a shs 14tooth lightweight piston and a 40 oo sorbo pad

is there any way that i could increase my fps by changing the cyclinder? (dont understand cyclinder portsto barrel length thing)

[mhealey]

Don't worry about cylinder to barrel ratio, that really only makes a difference with powerful springs. The stock cylinder should be the correct ratio anyways. I would say to increase fps get a double o-ring cylinder head and an air nozzle with an o-ring inside. Also, a generous amount of grease makes a BIG difference. My friend's gun was getting about 405 fps on a M140 spring with barely any grease (stock), then i lowered the spring to an M120 and greased it up quite a bit and believe it or not the fps actually went up to about 435 with the lower spring. So grease helps too

[Merana]

There's actually a lot of things you can do to increase FPS. The easiest is to go through your gun and eliminate anywhere the air could go except for down the barrel. The usual culprits are the air nozzle, cylinder head, and hop-up.
Once those are nice and airtight you have a few options:

• Tighter bore barrel (Less air escapes around your BB)
  
• Bigger bore Cylinder and Piston (more air being pushed down the barrel)
  
• Stronger spring (pushing air down the barrel faster)

Keep in mind that all of these have upsides and downsides so it pays to do your homework first.

[alpha5398]

i was looking at a 6.03 tightbore. will add more grease to cyclinder area. i use a mixture of silcon oil and white lithuem. silcon on orings and whitelithum in cyclinder. What do you use for grease?

[mhealey]

I use a silicone based grease called "super lube" on everything. i believe its sold on clandestine airsoft, you can probably also find it at some kind of hardware store. what you have should work fine though, silicone on o-rings and white lithium on gears is exactly what you want. also i just wanted to mention that although merana said you can get a bore-up cylinder, those are meant for m130+ springs only

[alpha5398]

knew that

[mhealey]

ok

[alpha5398]

regreased cyclinder area. stretched o rings has great compression, but when nozzle goes on it goes down.looking at new nozzles

[mhealey]

Try this one. I'm going to get it because i just cracked mine while trying to put the barrel/hop up back in (oops...)

[alpha5398]

ordered from there befor. great place. was looking at that one befor u showed me. sadley its out of stock. what size bushings do E1 p90's? looking to replace stock brass ones with some soild metal ones

[mhealey]

I don't actually know, on mine 4 are brass and seem to be 8mm while 2 others look like they are steel 6mm or 7mm. it's weird i have to look into it more

[jwberry]

They are 7MM.