Valve Stem Packing for Gasoline

[velvetfoot]

I got an old Kemp chipper/shredder yesterday and it works great (much better than the MTD pos I have).
Gasoline is leaking from the valve stem. I tried tightening the packing nut, but that didn't help. I'd like to try wrapping some packing in there before I attempt to take the valve off of the metal tank of the 8 hp B&S engine.

I see it comes in teflon or graphite. Which would be suitable for gasoline.

Thanks.

 

[Jags]

Interesting question that I asked to my buddy, Google. It does appear that the graphite stuff can be used in fuel application. I know it is common in water applications, but was unsure if the fuel would cause any issues.
From using this stuff in water application I do know one thing...get rid of all the old stuff. Actually scrape it out and replace with all new.

Note: in my reading I have also seen where the teflon is great at resistance to chemicals. Just say'in.

 

[velvetfoot]

I googled, but couldn't find much. It's all a matter of putting in the right search terms I guess. I just got a package of each. I think I'll try the teflon. Have to drain tank first.

I'm leery about willy nilly replacing the valve because who know if it won't take a part of the tank with it, lol.

 

[Jags]

Not really much you can hurt on the valve. Go for it.

 

[velvetfoot]

I'll try the packing first and replace the valve second.

Again, I'm digging the vintage Kemp chipper.
Interested in a used MTD? LOL

A thought just occurred to me: maybe I could switch the engines so it's not a total loss, although I think the MTD's is bigger, despite it's crappy performance.

 

[Jags]

Several factors in switching engines. Shaft size/height/length of output shaft, etc.

 

[velvetfoot]

True. If it won't work, I'll kick it to the curb.

 

[Jags]

That doesn't mean that it isn't worth the try. Just pointing out the homework that needs to be done first.

 

[velvetfoot]

I'm just so pissed off at that stupid thing. My wife wanted some more chips for a garden path, and just the thought of breaking out that pos was enough for me to act. It's only a $250 experiment, but so far, so good.

 

[heat seeker]

I seem to remember reading that you use a yellow Teflon tape for gasoline.

There just might be an O-ring in there, I've seen that.

 

[velvetfoot]

I just drained the tank and took off the nut. The stem came out as well. It is a needle valve, I guess you'd call it. It looks very fixable: indeed, a deteriorated o-ring was in there. Tomorrow's job is to rummage around the hardware store's o-ring bins (good luck to me).

 

[semipro]

from here: http://www.coleparmer.com/Chemical-Resistance

Teflon, aka PTFE shows excellent compatibility with gasoline. I realize that you're now looking for an o-ring but thought this still might help.

Chemical Selected:
Gasoline, unleaded

Material
Compatibility
ABS plastic D-Severe Effect
Acetal (Delrin®) A-Excellent
Aluminum A2-Excellent
Brass N/A
Bronze A2-Excellent
Buna N (Nitrile) A1-Excellent
Carbon graphite A2-Excellent
Carbon Steel B-Good
Carpenter 20 A-Excellent
Cast iron A-Excellent
Ceramic Al203 N/A
Ceramic magnet N/A
ChemRaz (FFKM) N/A
Copper B-Good
CPVC C-Fair
EPDM D-Severe Effect
Epoxy A2-Excellent
Fluorocarbon (FKM) A-Excellent
Hastelloy-C® A-Excellent
Hypalon® A-Excellent
Hytrel® N/A
Kalrez A-Excellent
Kel-F® A2-Excellent
LDPE N/A
Natural rubber D-Severe Effect
Neoprene B-Good
NORYL® D-Severe Effect
Nylon A2-Excellent
Polycarbonate A2-Excellent
Polyetherether Ketone (PEEK) N/A
Polypropylene C1-Fair
Polyurethane N/A
PPS (Ryton®) A-Excellent
PTFE A-Excellent
PVC C2-Fair
PVDF (Kynar®) A-Excellent
Silicone D-Severe Effect
stainless steel - 304 A1-Excellent
stainless steel - 316 A2-Excellent
Titanium A-Excellent
Tygon® C-Fair
Viton® A1-Excellent

 

[velvetfoot]

That list should help a lot when I go rummaging tomorrow!
I guess I could see if I could get a B&S part number.

 

[semipro]

If I recall correctly, Viton, Buna N and Hypalon are materials commonly used for o-rings for engine applications.