Shoebox F10 troubles - super slow

[AustinMatt]

I picked up a shoebox from a local guys for a screaming deal. Had the rod job done, included two seal kits. Still on a chain, but sounds fine. Tops my gun off (Gamo TC45 - 250bar) (200 -> 250 in 8 -10min). But it is struggling to fill a 45min tank. Like about 14 hours into it and I am just at 3400psi. And I started at 1800psi. The 14 hours is over the course of a few days, with me disconnecting everything, spitting out water, etc every couple hours.

This doesn't seem normal, even for the generally slow shoebox. Any idea what it could be? Where to start looking.

[Back_Roads]

 Seems about right for a chain drive version. not sure what PSI you are feeding into it that may be something to look into.

[AustinMatt]

On a large tank primary compressor at 120psi.

Electric motor has a 2016 MFG date on it. Chain is well tensioned and lubed.

[Hangtown-Shooter]

Are you certain your chain drive Shoebox is a 4500psi version? They also made a 3k version...

[mobilemail]

I thought the chain drive was the early model and the F10 was the later feature updated model that shipped with belt drive, auto lube pistons, etc. I don't have any idea what fill time is for the chain drive model, but the F10 specifies a 150psi input in the manual if I recall correctly, and fills my large carbon tank from 3300psi to 4200psi in about an hour. 

Any chance you have a leaking O-ring in one of the pistons?  A rebuild might be a good place to start, especially since you bought it used.

[Frank in Fairfield]

Not an F10 with a chain.
My Max had a belt (both of them).

[FuzzyGrub]

It sounds like it is one of the early models that has been updated with the hardened cylinders, but not a belt drive.   

On those and on the Max have the "clacker" shut-off.  The input needed to be set at 85 psi for that to work correctly.  Going to a higher input pressure would fill faster, but forgot if the shut-off kicks in early or later.   From description, don't think it is a shut-off issue. 

I never filled large tanks or guns, but your tank times seem long.  I think you have to check for leaks including any hoses and tank fittings.  If that is all good than look at rebuilding the bottom cylinder.   On these models, you have to lube the rods every 2 hours with lithium grease.

[limbshaker]

You either have an air leak, the check valves are sticking, or the pistons are improperly adjusted.

Go over the connections at the output ends of the cylinders with soapy water while it's running. Even a TINY leak will make it unbelievably slow and unable to build high pressure.

Lots of times the check valves get super gummed up from overlubing with white lithium. If you pull them out, check the seat where they seal for pitting that would cause them to leak.

My money is on an air leak, especially if it's been apart recently.

To check that it will build full pressure, hook it to your tank and turn it on, but leave the valve closed so that it's just filling the hose. It should move up the gauge to 4500psi within 30 seconds or so. I do this Everytime I turn mine on, and just open the valve on the tank when I see that it's working properly.

[AlanMcD]

I agree with everything Chase said.  I will add that when I fill my 45 min tank with my modified max, it fills at about 480 psi per hour of run time.  I expect that the original chain drive models were slower, and should do about 300 psi per hour if all is well.

Good lick isolating and fixing the leak.

[rsterne]

Yep not an F10.... I have an F8 and it is belt drive.... Generally when your fill times are unreasonably long you either have a tiny air leak (which may include the piston O-rings) or a leaking check valve (often due to dirt/grease buildup).... Don't forget, the original chain-drive models were only rated at 4 CF/hr, so a 66 CF tank would take about 16 hrs. to fill from zero to 4500 psi with everything working like new....

Check all your fittings, including the fill whip and Fosters, with soapy water, to make SURE you don't have a pinhole leak somewhere.... One of the trouble spots was the nut where the small air line attaches to the rear of the HP cylinder, the compression fitting often fails after a few removal/replacement cycles.... You have to remove that line to service the check valve....

Bob

[Hangtown-Shooter]

Matt, post a pic of your shoebox with the cover off when you have a chance.

[Back_Roads]

 Just this weekend I fired up my f10 looked like it was building pressure fine, came back 10 minutes later to see it not gain much more pressure, sure enough I did not tighten the bleed valve on the SB, gave it a final turn snug and pressure went right up.