Hello all, I have a problem with an old powermaster from the 70’s. It’s a buddy of mines gun and I was trying to get it working for him. I have changed all the seals, polished everything up, and it shoots great. I have one problem I can’t figure out. I would really appreciate any help. The pump handle when closed, doesn’t seem to want to stay closed very well. I am trying to figure out what exactly holds it In. It pumps fine, and closes. But just the slightest bump and it will fall back out from the barrel. Thanks so much for your time.
Crosman Crossman 760 Powermaster
- Thread starter Jcalloway
- Start date
after doing some reading the only thing that hold the pump arm up is the suction the piston cup creates between it and the valve when closed
i looked at many of the 760 parts diagrams and there is no hold mechanism like on a Daisy 880
it is only vacuum
not what you want to hear and maybe i am wrong but there is nothing on the front of the receiver halves or the tube
now could you Macgyver something, i don't know i do not own the rifle
good luck
Mike
i looked at many of the 760 parts diagrams and there is no hold mechanism like on a Daisy 880
it is only vacuum
not what you want to hear and maybe i am wrong but there is nothing on the front of the receiver halves or the tube
now could you Macgyver something, i don't know i do not own the rifle
good luck
Mike
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It is likely, either the adjustment on the piston length (early ones are adjustable) to hold proper pressure or possibly a worn front hole/pin on the cocking handle. (If it is not tight and wobbly)
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I kind of thought that may be the case. I just figured if it was tight enough to pump the gun up, which it’s way better than ever, then it would be tight enough to hold the piston in place. I did end up putting a new piston in it, so it’s new. I have it adjusted as far out as possible before it binds. Maybe it’s a very small window and I j
Should give it another go and adjust it out a little further.
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What exactly are you referencing? I did notice there is a good bit of air when I fire it that comes out around where the front of the bolt shoves the bb in. I noticed this because I used a lighter oil when I was testing it and noticed it sprayed a little when firing, but I don’t see a way to tighten that fit up.
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There are YouTube videos you can use to help with the adjustment to the piston. If the pumping handle is wobbly then it will need shimming.
I misspoke and meant pumping handle not cocking handle in the first post. Sorry
I misspoke and meant pumping handle not cocking handle in the first post. Sorry
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if you go to Crosman they have all the manuals and parts breakdowns and the thing with the 760 is there are 7 versions over time
so, we here on the forum don't know for sure which one you have
the early ones you could adjust the piston length to fine tune the assembly
and then that went away
like the Daisy 7-7 pistols they can have their pistons heads adjusted so the cocking handle is in the right place
now if the that is not the case you could add some sort of material to either the pumping handle rear or the clam shell to add some resistance so the pumping handle will not flop open
now here is the Crosman page that the 760's are found look through the different models to find your
but in any case, there is no holding mechanism on any model
https://support.crosman.com/hc/en-us/sections/200658060-Crosman-Air-Rifles?page=3#articles
so, we here on the forum don't know for sure which one you have
the early ones you could adjust the piston length to fine tune the assembly
and then that went away
like the Daisy 7-7 pistols they can have their pistons heads adjusted so the cocking handle is in the right place
now if the that is not the case you could add some sort of material to either the pumping handle rear or the clam shell to add some resistance so the pumping handle will not flop open
now here is the Crosman page that the 760's are found look through the different models to find your
but in any case, there is no holding mechanism on any model
https://support.crosman.com/hc/en-us/sections/200658060-Crosman-Air-Rifles?page=3#articles
Upvote 0