Power troubles

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dyer
Posts: 29
Joined: Sun Feb 15, 2015 9:28 pm

Power troubles

Tue Jun 26, 2018 6:46 pm

I have an airarms 410 carbine with a airmasters 88 (dave welham ) regulator fitted it has bee unused for about 3 years and I have decided to sell it .
Unfortunately when i got it out to check it over it had developed an air leak . I managed to narrow this down to the reg, I decided that as I like a tinker and also to find out how stuff works I would have ago to fix it .Also I would have to take it to a gunsmith to sort it ,so I thought even if I cant fix it will still be going there .
Anyway stripped gun got out reg replaced outer o rings and the one on the stem inside the reg re assembled it all filled it and much to my surprise no leak ! then i thought even though I made sure everything went back in as it came out I ought to check the power which was 7.5 ftlbs. so i took out the reg again and made a slight adjustment and checked again this time 5ftlbs . so out it came again adjusted reg again in the opposite way from last time ,tested 2ftlbs !
Now i am really confused and on the verge of taking it to the gunsmiths to sort it , but would really like the satisfaction of doing it myself .
So i am hoping that one or more of you people with a lot more experience and knowledge might be able to point me in the right direction.
As i typed this a thought has occurred to me I did notice the bit of the firing pot that is left was loose , not sure if this would have any bearing on the problem.
thanks in advance
Duncan

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Blackbaronfish
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Location: Nuneaton

Re: Power troubles

Tue Jun 26, 2018 10:35 pm

The fireing pot shouldn’t be loose as this measures out your air. See if you can unscrew it a little, then check over the chrony

BBF
Did I mention that I'm the only one to have attended EVERY meet since we started

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dyer
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Joined: Sun Feb 15, 2015 9:28 pm

Re: Power troubles

Tue Jun 26, 2018 11:24 pm

Ok will do
thanks
Duncan

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TenMetrePeter
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Location: Luton Beds UK

Re: Power troubles

Wed Jun 27, 2018 6:12 am

Isn't there a recommended length for the pot to be protruding as a starting point like 57mm? Then a grub screw to tighten it?
I havent done one but I've read it loads of times on here.
(Search for 57mm on this forum)

I didn't read here or on the other forum what you have tried with the power/venturi screw under the cover screw.

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dyer
Posts: 29
Joined: Sun Feb 15, 2015 9:28 pm

Re: Power troubles

Wed Jun 27, 2018 6:52 am

Thanks for replies, all I have done at the moment is adjusting the regulator. I will move the firing pot ( won't be until tomorrow though) although because I have a reg fitted it is only short not full length so will have to experiment! Could take a while!
Cheers
Duncan

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Blackbaronfish
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Location: Nuneaton

Re: Power troubles

Wed Jun 27, 2018 7:49 am

Is that you on the BBS saying that you have fiddled with everything :lol:

BBF
Did I mention that I'm the only one to have attended EVERY meet since we started

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Roger5
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Joined: Sat Jul 25, 2015 8:04 am
Location: Hampton middlesex

Re: Power troubles

Wed Jun 27, 2018 7:56 am

Blackbaronfish wrote:
Tue Jun 26, 2018 10:35 pm
The fireing pot shouldn’t be loose as this measures out your air. See if you can unscrew it a little, then check over the chrony

BBF
Screwing in increases pressure on firing valve making it harder for hammer to open the valve, screwing out does the opposite, and the 57mm mentioned by Peter is for an unregulated rifle and shouldn't concern you, being that yours has a reg fitted. Rog

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TenMetrePeter
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Location: Luton Beds UK

Re: Power troubles

Wed Jun 27, 2018 8:22 am

Hello. Armchair expert here again. I think you still need to know for sure what the reg is set to and without a reg setting tool I dont know how you know what it is set at. Typically you set it to say 90 bar then fiddle with the venturi to set the power. I believe you took all the bellvilles out to degrease them? Did they go back in the same pattern? eg ()()()() or (())(()) etc.
To get really low powers like 2.5 ft lb something drastic has happened in the rebuild. Did you grease the hammer rail for example?

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dyer
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Joined: Sun Feb 15, 2015 9:28 pm

Re: Power troubles

Wed Jun 27, 2018 8:27 am

It is me on the bbs, but I have only fiddled with the reg ( changed o rings to stop leak then adjust reg both in and out ) there have however been an awful lot of suggestions of stuff I should have fiddled with but I haven't ...yet
There were no bellville washers just one spring . The reg pressure. ( according to my gauge )is set 100bar but I have tried it at 80 to 140 which made no difference
Duncan

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dyer
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Joined: Sun Feb 15, 2015 9:28 pm

Re: Power troubles

Wed Jun 27, 2018 8:29 am

And no I haven't been at hammer rail . All I have done is removed reg no screws have been tweaked !

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