Whisperlights in Winter

Hi
I camped out Saturday and Sunday nights off Goose Eye in Maine, in some pretty cold conditions, and my (one-year-old!) Whisperlight was pretty exasperating to deal with. Here's the big question: why does my pump whimp out when it gets really cold? Sometimes when it gets bitterly cold, the pump just won't pressurize. That happened to me this weekend on Saturday, right when I got to my campsite in the afternoon, and I fiddled with it a bit and it made a 'pop' noise, and then worked. (Though the pressure didn't seem great). So I started putting it in my pocket, along with a fuel bottle, and then it seemed to work OK. But then, randomly on Sunday afternoon, it just stopped pressurizing again, and could not be convinced to get back in the game. I wound up building a fire to boil water. When I got home, it was working fine again.

I got a new whisperlight last year, in part because two years ago I had the same problem while using a new pump with an ancient whisperlight. I figured I'd just upgrade to new everything, so I returned the pump that failed and got a whole new stove (complete with new pump, which let me down this weekend). So what's the deal?
Any ideas on some basic Whisperlights in Winter issues?
Mariachi

Doesn't help, but there's a warning in the manual, might be standard disclaimer type stuff;

the manual said:

When temperatures are below -10 F (-24 C), O-rings may be stiff and prone to fuel leakage.
Use extreme caution in temperatures below freezing.

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yeah i know about that - i didn't have any leak issues though.

Whisperlights are usually pretty reliable in winter. If you havent done it, you may want to pick up a rebuilt kit and rebuild it. A lot of people skip using adequate amounts of silicone grease on the o-rings. The other thing can happen is the pump "cup" can get dried out or it takes a "set" and doesnt inflate when the pump is moved. Sometimes you can grease it up and make it pliable again. I think they include grease with the kit but automotive part stores used to carry it.

The other issue with whisperlights is that in real cold conditions with big pots, enough heat can be reflected off the bottom of the pot to melt the snow under the stove making a vapor cloud. This cloud rises and gets into the atomized fuel jet (which is cold fuel) and freezes in the orifice paritally choking off the fuel flow, the pressure in the fuel keeps it partially open so the stove runs at low fire but you cant crank it up. The solution is to use a stove base like a piece of license plate. It a tough one to figure out as once the fule is turned off the heat radiated from the burner melts the ice in the orifice.

It's just the pump giving you a problem? Pressurizing the fuel tank?

I would follow all the "Pump maintenance" steps in the manual, including the lubrication (drop of oil) of the pump cup. Also make sure that no moisture is getting in there and causing icing.

I've used a Dragonfly without incident at -26. Pumping was no problem; however, it took a fair bit of priming to get it hot enough to be self-sustaining and "jet".

The pop noise was probably air escaping from the fuel bottle- and in doing so, knocking the o-ring back into place.

It's definitely not a bad idea to grease and/or replace your o-rings every so often. If your stove is older (and it sounds like it is), this might help to rejuvenate it for winte use. You can buy kits with replacement o-rings that also help you to clean and service the stove and keep it in good working condition.

I had a pretty spectacular failure with a whisperlite in winter once- It was on the Northville-Placid Trail in January with the PSC Outing Club. We'd just gotten to the Silver Lakes lean-to after a long 10 mile day, and I was getting the stove primed, when all of a sudden it started squirting fuel all over the inside of the lean-to. Since it was already lit, it wasn't long before their were flames roaring up inside the lean-to. Fortunately, I quickly grabbed it and tossed it as far as I could into a snowbank, where it sputtered and kept burning for the next 5 or 10 minutes before going out. The stove never really worked the same after that.

Sometimes the change in elevation can effect the bottle pressure and alter the effectiveness of the pump. Try releasing the pressure by unscrewing the pump from the bottle. Tighten the pump back to the bottle and then repressurize the bottle.

MindlessMariachi said:

Here's the big question: why does my pump whimp out when it gets really cold?
...
Any ideas on some basic Whisperlights in Winter issues?
Mariachi

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Yes, you have the wrong stove. Try this:SVEA 123.

Raise your hand if your stove will light all the time, every time, no matter how cold -- mine will.

*Raises hand*

I use a whisperlight.

Thanks for these comments! The pump and stove are almost brand new. AND when I heard the 'pop' i'm pretty sure it was not even screwed into the fuel bottle. (I was unsuccessfully trying to twist the plunger out while wearing mittens). I'll dig into it and check out those o-rings. And maybe the cup needs more oil in cold temps, becasue this one is pretty new? It seems weird that it would go back and forth from working to not working. I thought maybe there was something frozen in there that was screwing it up.

At one point I had my bottle nicely pressurized but it was still not working great. I think I had ice in the fuel line maybe - I shook the whole stove and that got it working really well.

Anyway, the upshot is that I was stoked I was able to build a fire; it would've been much more of a hassle to find wood if there was more snow!

I'll try to do a trip report later. It was a fun trip. I went up a little beyond the second ledge up on the Wright Trail, headnig up to Goose Eye. The wind was ferocious up there! I didn't go to the summit, because while making soup midway up I started getting fed up with the stove. I didn't want to get all the way to the summit, have drank all my water, and not have a stove - it'd be a loooong cold way back to civilization like that.

BF said:

*Raises hand*

I use a whisperlight.

Click to expand...

Now raise your hand if it has been doing that for forty years.

Msr stoves are pretty reliable. You may need to pop out the pump cup and flex it out and oil it. And yes, I have a 123 but it is in retirement.

For me, it's the whisperlite that's in retirement because my Svea 123 always works...

For the 123 users, what do you prime it with? I've been using a brass tube like a straw, put your finger over the end and pull a bit of fuel out, then close it up, put the top back on, and light it... but that's a PITA.

The 123 gets primed in summer with a match or two held under the tank, while the valve is open. When you get enough to light, blow out the match and close the valve. In winter, it's usually a candle. You have to be pretty careless to heat it so much that liquid fuel spurts out of the nozzle. Under very rare circumstances in the summer, I've been able to prime it as suggested in the instructions by holding the tank in my hands. But that's more of a parlor trick, IMO, than a reliable method.

This reliable procedure is really the critical difference between the 123 and the Optimus 8R and its ilk. The latter need the pump. The optional 123 pump was often bought by unskilled 123 users who looked longingly at the 8R -- much like an appeal to Tim Allen's need for "More power!!!"

If your stove is pressurized and you have a weak flame, the problem is almost certainly a clogged fuel line or jet. Bad fuel (or a dirty fuel bottle) would explain intermittent poor performance - it clogs, works poorly, unclogs and works great, then clogs again.

To prevent clogging, use good fuel and keep dust and debris out of your fuel bottle. Also, after you turn your stove off, shake the burner assembly back and forth. You'll hear a little pin clicking up and down. It's there to keep the jet clean and free of blockages. Do this every time after you finish cooking. It takes less than 10 seconds and will improve your stove's performance. You can see the pin if you look carefully under the burner exactly where the fuel comes out. Don't try to look there while it's lit.

And neither my Whisperlite nor I have been alive for 40 years, but I'll go ahead and raise my hand and say it works in any conditions. Although I hear (read) that white gas freezes at -22 F. Anyone ever run into that problem? I've cooked with mine at -20 and didn't have even the slightest issue.

hikerbrian said:

Although I hear (read) that white gas freezes at -22 F. Anyone ever run into that problem? I've cooked with mine at -20 and didn't have even the slightest issue.

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Not freezing (you'd never want to be out in temperatures at which Coleman fuel solidifies ).

But the flash point is indeed -22ºF/-33ºC, as shown on the spec sheet from Coleman. This means that below that temperature, the fuel will not ignite in air.

BUT we're talking here about the fuel temperature, NOT the air temperature. So a Coleman fuel stove will frequently operate at air temps below this because the fuel itself has not been cooled sufficiently.

BTW, if you want to know the distinction between white gas and Coleman fuel, check out this old VFTT thread.

i usually put my fuel bottle in my pocket at cold temps. does that actually make a difference? I feel like on a sub-zero day, the fuel probably ignites better if it's not so cold, but I don't know if that's for real or not. Or can I free up that pocket space for other stuff?

sardog1 said:

Not freezing (you'd never want to be out in temperatures at which Coleman fuel solidifies ).

But the flash point is indeed -22ºF/-33ºC, as shown on the spec sheet from Coleman. This means that below that temperature, the fuel will not ignite in air.

BUT we're talking here about the fuel temperature, NOT the air temperature. So a Coleman fuel stove will frequently operate at air temps below this because the fuel itself has not been cooled sufficiently.

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Ah, thanks for that link, it all makes sense now. Amazing how many websites say the melting point of white gas is -22 F!

To clarify, the fuel will burn at a temperature below its flash point, however you need to ignite the actual fuel, not the fuel/air mixture that is above the fuel. (Flashpoint is defined as the temperature at which the material will produce a flammable mixture of fuel and air in the space above the fuel.) This would seem to be semantics, but actually it is relevant: when you prime your Whisperlite, in normal temperatures all you need is a spark from a lighter to ignite the fuel/air mixture, which will then ignite the fuel in the cup. However, when it is very cold (below -22 F), you need to actually ignite the liquid fuel with a match or other flame, a spark above the fuel will not work. I have observed this phenomenon, and now it makes sense! Yay science.

After reading the msds, I see that Coleman fuel is a mixture mostly of heptanes and pentane with a few other hydrocarbons. The melting points of these chemicals are -130 F and -202 F - you're right, no matter how good the bragging rights would be, I wouldn't want to be out in those temps!

And I think you can free up your pocket for other stuff - as long as you have a source of flame, you'll be able to ignite your Coleman fuel without a problem.

Thanks for straightening me out on flash point. I knew while writing it that it was probably incorrect. (Just don't let my sister, the ChemE PhD, or her husband, also a ChemE PhD, know about this ........ )

sardog1 said:

Now raise your hand if it has been doing that for forty years.

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Svea's crap . (Me and a friend used to actually have this argument.) I was an Optimus 8R user from 1973 through about 1990. When I got back to winter backpacking I tried to find it's closest modern relative and bought a Primus Himalaya. I have had no problems in winter and the initial priming flare and subsequent jet noise give me nostalgic goose bumps every time .