Fixing a Daisy Avanti 747 (I hope!)

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!

32 thoughts on “Fixing a Daisy Avanti 747 (I hope!)

  1. Thanks for the help. Oiling it seems to have done the trick. I couldn’t find any non-detergent oil so I used 3in1 oil. I hope it won’t ruin anything.


  2. Brandon,

    In this instance I think 3-in-1 oil will do fine. Just don’t use it in a CO2 pr a precharged pneumatic gun.

    And thank you for the feedback!

    B.B.


  3. With the izh 46m It is best to not oil at all. Because once you oil it, it will flush out the factory lubes and require oiling very often as you have seen.

    So either oil very often, or dont oil at all.

    At the club the 3 izh 46m’s are never oiled, and have been going strong for a couple of years now with continous use.

    The only downside to oiling, is you have to do it often, and if you forget, it can cause velocity to fluctuate.

    The rubber seals around the breech should be periodically lubed with silicon grease.

    James


  4. James,

    Thanks for your observations. I frind the 46M to be a more robust design for some reason. The regular 46 seems to require moref attention than the M model.

    B.B.


  5. I have experienced the same loss of pressure with my 747. I will try the lube to see if it helps. I am also baffled by the procedure for pump head adjustment. What is supposed to happen 1 1/8″ from the frame? The pressure I feel on the pump handle starts almost immediately when I begin pumping. I must be missing something – can anyone explain it better than the manual?



  6. BB-
    Is the Daisy Powerline 717 discontinued? Cannot find it listed at Daisy or Pyramydair.

    Thanks,

    Ray

    BTW- If discontinued and one is able to pick one up would you recommend it – say brand new for about $95?




  7. I agree with the comment on the 1 1/8″ adjustment——-hard to discern. The gun (mine) needs to be dry-fired a few times before it has the power to shoot a pellet. It seems like air is lost at first.

    ———————D.G.


  8. DON’T COCK THE GUN WHEN ADJUSTING THE PUMP HEAD!!!

    Of course there will be resistance if you cock the gun – that’s how it’s charged for firing. Read the owner’s manual before attempting to adjust the pump head.

    If you DON’T cock the gun, the resistance will be easy to feel. Adjust it until the end of the pump handle is 1-1/8″ from the frame when the resistance starts.

    B.B.


  9. Actually, if you don’t cock the gun, there is zero resistance! The manual isn’t clear on the subject. Daisy told me to “cock” the gun and then adjust but at best its a guess (hit&miss) adjustment. I never got it closer than 2″ and finally said “good enough”.
    D.G.


  10. D,G.

    I guess I don’t remember the procedure as well as I used to. It’s been a few years since I did it, so cocking probably is part of the process, but a cocked gun will try to store air pressure, like the other reader said.

    In an uncocked gun, there is zero resistance until the lever gets close to the side of the gun, then there’s a definite stop about an inch out. That’s what you are adjusting. It was no guess; it was a positive stop. I think your gun may be way out of adjustment.

    B.B.


  11. You were right! My gun was way out of adjustment, from day one! You were also RIGHT on the “no cock” for setting the 1 1/8″–1 1/2″ pump adjustment. It now works great, like it should, thanks to you—and seems to have more power.
    D.G.


  12. D.G.,

    I am so happy that your gun is now working as it should. I think you will now grow very fond of this gun, as so many other owners are.

    Thanks for the feedback.

    B.B.


  13. After all the great comments about the 717, I purchased one without the manual, I have done the google thing and cannot locate an online manual, at Daisy or elsewhere. Can someone point me toward a pump adjustment proceure?
    Many thanks for any help,
    -Pol


  14. Pol,

    Here is the procedure, as I remember it. Do not cock the gun but open the pump handle and then move it toward closed. It should pause slightly just before coming to rest against the side of the frame. In this position measure the distance of the tip of the handle from the frame. It should be 1 to 1-1/8-inches. If it’s more or less, here is the adjustment procedure.

    Do you see the castellated nuts inside the pump tube near the fulcrum of the pump handle? Insert a flat blade screwdriver with a wide blade into the notches of the two nuts and twist. This will rotate one of the nuts. Keep rotating for a few twists and then measure the handle space again. You will soon deduce which way to twist the screwdriver blade.

    B.B.


  15. B.B.
    I’m very grateful for your prompt reply, perfect explanation, and incredible archive of know-how.
    Very best regards,
    -Pol



  16. B.B.

    Very sound advice, thanks. The adjustment was easy, only two clicks needed to add some ooomph. Recoil is nothing with this powerline 717. My groupings are slightly better than my Marksman 2004, but I’ve only had one session of 100 shots, and the hiccups.
    I’m looking forward to getting better acquainted with this one after some oil and good weather.

    Thanks again for the tips on this page, and the other pages as well!
    -Pol


  17. Thanks guys, I have a 747 and a 717 both were not quite right. I add some silicon oil and adjusted without cocking and both now shoot well. I use these to teach my kids. I replaced the handle on the 747 with nice walnut handle from 777 model. The 777 is now discontinued, thanks again


  18. When I cock the gun I can hear air rushing out and in less than a minute it’s all gone. Can you replace the seals?


  19. Before you start replacing things, how long has it been since you oiled your pump seal?

    If you haven’t done that, do it now. The procedure is in the manual.

    If you don’t have the manual, oil the felt washer in front of the pump head (visible with the pump handle extended. Use Crosman Pellgunoil or non detergent 20 weight motor oil.

    B..


  20. B.B.Pelletier(neat handle),
    It was recently oiled using 3 in 1 oil. Maybe the oil I used is to light. The adjustment instructions in my manual were followed.


  21. Okay, the 3 in 1 oil may be the problem. It is the wrong kind of oil for pneumatic guns.

    Try a heavy dose of Pellgunoil or 20-weight to try to flush out the 3 in 1.

    Otherwise, the gun has to be sent to Daisy to be resealed.

    B.B.


  22. B.B, I talked to Daisy and ordered a seal kit. 7-10 days and I may be in business. I’ll let you know how it works.
    Lakeguy




  23. I am glad I found this link. My 717 was in need of adjustment. I now have it set 1 1/8″ off the frame. What a difference. It now barks when shot. I will Chrony it and post the results.


  24. I've found that a 1/2 pump immediatley followed by the "full pump" will yeild more consistant shots! and reduce the "leak downs"
    I believe this "sets" or "seats" the seals try it!

    MH


  25. I was glad to see the page is still here, I swapped out the pumphead, valve assembly and barel on my 717 today. The pump adjustment procedure you posted came in handy again today.
    Thanks again.
    -Pol


  26. I am so glad to find the answer I needed. I was using light gun oil and it did not last any time. Now with the motor oil I find it work great. Thanks for the information.


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