by B.B. Pelletier

Today’s post was suggested by a question we received yesterday.

The question
I have an Avanti 747. The first one I received would not hold air out of the box. The replacement sent to me has begun to periodically let air hiss out after being pumped, but it still shoots. Do you know what is causing this, is it something I can fix or do I have to keep sending the gun back to the manufacturer?

The answer – I hope!
Well I do have a couple of suggestions. Most of them are found in the 747’s owner’s manual.

Before we get started, you need to know that the 747 must be cocked before the pump mechanism will work. The bolt has to be pulled all the way back until a click is heard. Until that is done, no air can be pumped into the gun.

First
Are you leaving your gun pumped longer than five minutes? Daisy warns not to do this because the pump piston head is pliable (as it must be to seal the air when pumping). It cannot hold the pressurized air longer than a few minutes, so you should always shoot the gun within a few minutes of pumping. This is true for all single-stroke pneumatics, not just the Daisy.

You don’t have to race to shoot the gun. It should hold fine for a few minutes. But, if you habitually wait longer than five minutes to shoot it after pumping, your pump seal may now be very weak and start to release air sooner than it should.

Second
This step is MOST IMPORTANT!
Are you lubricating the felt wiper as described in the owner’s manual? The felt wiper is a felt ring on the Daisy; on other guns it may be just an O-ring or even the synthetic pump head, itself. Daisy used to recommend using 20-weight non-detergent automotive oil, but pure silicone oil such as Crosman Pellgunoil works well, too.

How often you should lube depends on several things, such as how much you shoot, but airgunsmith Rick Willnecker once told me that it’s impossible to over-oil a CO2 gun. I believe that holds true for a single-stroke pneumatic, too. The oil is pumped into the compression chamber, where it gets blown onto all other seals in the firing mechanism when the gun fires. I oil my IZH-46 at least once a month if I’m shooting it a lot and EVERY time I take it out of the case if it’s been several months between sessions. I put five drops of oil on the felt wiper, which is a rubber pump seal on the 46.

I just got my 46 out to confirm what I said and, sure enough, it was dry. It took a double oiling to get her going strong, again. I think the 46 is unique in needing that much oil. I don’t recall either of my Daisys being that bad. And, for the record, my Beeman P2 needs very little oil!

Third
Daisy’s 747 owner’s manual has a pump-head adjustment procedure. I had a 717 and a 777, and they both had it. First, you go through a procedure to see if the pump head is correctly adjusted. I believe the pump handle has to stop 1″ to 1-1/8″ away from the frame to be right. If an adjustment is required, it’s a simple procedure with a flat-bladed screwdriver to adjust the length of the pump rod and pump head (the seal).

Now you can do something for me!
If you try these things, please report back how they work (or don’t work, if that’s the way it goes). Make your comments to this posting, so others can read it. Unless we hear from you, I’m just somebody babbling on. I want to know if any of this stuff works. Or not!