Brand New QB78 - All I Get is Hissing

[London177]

Hello everyone,
My brand new fresh out of the box QB78 Deluxe seems to be a dud
I've called the dealers but their CO2 man in not at work until tomorrow.
I am not going to start stripping it down but can anyone offer any advice as to what may be at fault?
I inserted two CO2 bulbs as per instructions with rifle cocked. Secured the cap as per instructions etc.
Gave it a dry fire. A nice puff of gas and sound from the muzzle
Insert a .22 pellet.
Aimed at target.
All I get is the sound of gas escaping from some place near the breech area. This lasts for around two to two and a half seconds.
I've tried cocking it and firing it a dozen times but no luck  :0 All that happens is the CO2 continues to "leak" away.
Any ideas?
regards,
Alan

[IJL]

Hi Alan,
Thats probably a return to shop call as either the valve or it's outer seal is leaking (sounds like the seal if it leaks down the back end of the tube) BUT you could try this:-
remove the CO2 cap and the cylinders
with a LONG WIDE screwdriver insert it into the CO2 tank and engage the slots in the back of the valve, If it will turn clockwise then tighten it up, we may be on a winner.
Now
Open the bolt
Insert an empty CO2 bulb, nose first, then a full one, nose out
re fit the cap as normal
Does it still leak?
if not you are done
if it does then close the bolt
can you hear the CO2 at the muzzle?
If so then it's probably the valve seat is faulty if not then the seal we tried to tighten has failed either way thats either a return to shop or send it to your favourite tuner/repair man, unless you want to get your hands dirty.......

Ian.

[CharlieDaTuna]

Ian is probably right. I'd guess the valve stem seal. It takes just a little tiny bit of contamination for it not to seat, just a speck of metal or dirt will do it. Not a tough fix to repair if the seal isn't damaged. Usually if it's not damaged you can clean it up and very lightly resurface the sealing surface with a lot of care. There is a lot of info on my website regarding tuning and modding. Clean everything thoroughly when reassembling.

[London177]

Hello Ian,
Thanks for the info' and help.
I am very red faced
The problem was a jammed pellet. Silly me. It was lodged about 5" from the muzzle. I used a plastic rod to push it out. It was covered in brown muck and the hollow end of the pellet was stuffed with a woolen like substance. The pellet was very clean when I put it in and I am quite certain it was not deformed.
Anyhow, I have now put about thirty pellets through it with no problems.
I guess the gas escaping was just because it could not get past the pellet so bled back through the breech.
I am sorry to have troubled you.
Thanks again,
Alan

[London177]

Thanks Bob. I think I posted my reply to Ian a second or so before you sent yours. As you'll see it was a jammed pellet. But thanks for answering my pleas for help.
regards,
Alan

[ribbonstone]

...they come shipped with a cosmoline/earwax type "gunk"...it's literally a long slow boat ride from China...and until you get that gunk out of the barrel, are going to have problems.

If it's still leaking, and is brand new, would refer it to the shop (or importer).....can usually get them working again, but why go through the take down/reseal if you don't have to?

[London177]

Hi ribbonstone,
I did indeed clean the barrel. Earwax is an apt descrition of the muck that came out
Since the cleaning I've put through about 100 pellets with no problems.
You know what it's like. You get something new and if it is not perfect straight off a little panic sets in....hehe
Anyhow, I think all is well now. Besides, I am going to send it to Ian so he can cast some of his magic spells over it....
regards,
Alan