Random Thought on Hand Pumps and a question

[Stripminer]

Random Thought

It occurred to me this evening as I was pumping up my new Gamo Urban with my "imported" hand pump that hand filled PCP rifle could be an Olympic sport.  There I was taking aim from across the basement, my heart hammering in my chest from my pumping session, trying to hold on target. You see, there really is no need for cross country skis and a metered track through the woods.  Just hand out cheap Amazon pumps and let the guys and gals start at zero and then pump until full.  Let's see who can hit the target at any distance then!

Question

My "imported" pump does not appear to be working as well as all of those 4 1/2 stars would lead you to believe.  After a few pumps a tremendous suction sets in and pulling the pump handle upward to fill with air becomes a challenge. I find that a quick back and forth will sometimes clear this issue and I can fill my rifle easily.  The handle does get stuck in this manner very often and I believe that my quest for Olympic Gold in the PCP hand fill category is at risk.  Anyone have any experience? I think I will return this one and roll the dice again (agree?)

Thanks,  - Tom 

[null]

That is likely a bad seal.

Did you use silicone grease on it before using it?

My Hill MK4, I use NLGI 2 silicone grease on it like every 10 fills or so. I wipe off the old, and put new on. I've never had an issue, and I've filled large air guns with it. Although, I've been using some silicone grease from Tim Hill, because it is easier to dispense.

Also, you want to be slow and easy, the less heat build up the better.

Whatever you do, don't use WD40 or other stuff, as you can have a dieseled explosion in your airgun and/or pump.

[tracker1955]

Tom, my new one is doing the same but my understanding is I simply need to unscrew the top and lube the check valve parts and center shaft and the problem will go away. Others I've talked to that have had this problem were fixed once lubed internally with silicone oil. My instructions (after I read them) recommended lubrication before use. I haven't bothered to lube mine yet as I normally fill from a tank, and just bought the pump while on sale as a backup. Maybe since I'm off tomorrow I'll get into it and see if it resolves the issue which I'm confident it will.

[ranchibi]

Tom, that is too funny! Hand pumping will bring the heart rate up and muscles will fill with blood....no  cross country skiing needed to test ones skills! LOL! Like said above, lube center piston with pure silicone oil also the inner tube housing (wipe down with paper towel to clean) and make sure o'rings are lubed, this will make pumping less "sticky". Just make sure to pump slowly and methodically so as not to build up heat and use your body weight to drive the piston down slowly with str8 arms...I'm only 145lbs and can hand pump using this method....like the tortoise and not the hare! LOL!

[OTmachine]

Check valve(s) sticking