Daisy 717 mid-pump hiss

[512k]

Hello there, I'm a new poster although I have been lurking in the shadows for a while

I'm also quite new to airgunning in general, and I've just come into possession of my Granddad's old gear. It all seems to be in good to excellent condition, but hasn't been touched for at least ten years so I'm guessing it will need a bit of TLC to maximise performance.

One of the guns is a Daisy Powerline 717 in .177, which I really enjoy shooting and it seems to be very accurate even in my newbie hands. The lever was originally poorly adjusted so that there was no resistance whatsoever when actuating the pump lever before cocking the bolt. This meant that the lever flapped around a bit when un-pumped and I believe also means the gun was operating at less than maximum power. I've now adjusted it as per the instruction manual. However, after about 50 shots it has developed a slight hiss during the pump stroke, around the point of maximum resistance. This stops once the pump stroke is complete however, and it seems to hold pressure ok.

I'm assuming this means that I'll need to replace at least one seal, but I could be wrong. Can anyone point me in the right direction, or is this actually normal? It only seemed to start happening after I adjusted the pump lever, but I made sure to stay within the specs.

[peteswright]

Just noticed this post. Sorry you've not had any help yet. I can't help as I don't have experience of this pistol but I'm sure someone will be along shortly to give advice. ATB. Pete.

[Benelli B76]

Should be an easy fix, this pistol has an O ring on the pump head and an O ring on the valve body. I could repair it but only work on my own and friends pistols.The only other chap I know who may do it is Lawrie Amatruda who can fix this type of pistol. He is well known on this site.

Baz

[savantguarde]

Its either the o-rings or the valve. if the hiss is coming out of the barrel then its the valve. O-ring wise I have used commonly available o-rings from the box-style kits in a 717 with no problems. if its the valve then it really does require looking at. Although if you are handy I recommend stripping the 717 as its not that complex when you get in there. If you can get someone local to look at it then so much the better but if you are still having trouble drop me a PM. A touch of talc will help you visualize where the air is leaking from (small amount!)

[pcusername]

Before you start stripping it down or getting someone to look at it examine the felt pad on the piston,It's often dry.Soak it with a few drops of pelgun oil.This will get picked up on the piston seal when pumped and lubricate the internals.This often cures a leaky pistol.

[512k]

Many thanks for the pointers, I'll try oil on the felt wiper first and then break out the screwdrivers to check the O-rings and valve if that doesn't sort it. I'm quite comfortable with taking things apart, and yes it doesn't look that tricky to do. No big springs to contend with