My Jet Boil stove does not simmer. Every time I try to turn the fire down it goes out.
Is this normal to all Jet Boil stoves, or is it just mine?

How old is it? What fuel are you using?

I have two Jet Boils, one from 2005, one from 2010. The older one is a little harder to tune to simmer; if there is any wind, simmer is almost impossible. The newer one seems a little better, partly because the valve has a wider control. The newer stoves seem like much more of a cheap commodity item; you can't get the igniter replacement anymore.

The propane/isobutane ratio changes as the fuel is used, and the flame behavior seems to depend on the amount left in the can, and temperature.

It's about two years old. It uses the fuel canister that is made to fit inside the unit. It's a mix of Isobutane and Propane fuel. I usually use it in cold weather, camping at over 10,000 feet, and I try to run the canister dry before changing. The igniter never works in the mountains. Love the design, compactness, but I'm not sure it's very dependable for winter.
Thanks for the feedback.

Even for modest temperatures (say, a 25F morning), I have to warm up the cartridge. Else the flame is pretty weak to start. I also try to keep the cartridge on a somewhat-insulating surface -- tough, because such surfaces are typically not too stable. I never remember to put the cartridge in my sleeping bag at night.

Several good ideas. I used the heat from my hands to keep the burner going last weekend. Unfortunately, I'm still stuck with a stove that just refuses to simmer. Next time, I'll put a new warmer canister on to see if I can simmer with it.
Thanks again.

I got mine in January 2007 (I know because I mentioned it in a trip report here on SP) and it's never given a satisfactory simmer. I don't try to use it for anything that requires more sophisticated cooking than "boil some water, add dehydrated food, let sit for five minutes".

To simmer on a stove that's running at full heat, you could use a metal or stone plate as a heatsink/diffuser, and place your pot on top; or you could lift the pot a cm or so higher than its normal position, or you could put a smaller pot inside the main pot. With any of those ideas, you'll need to be very wary of tip-overs.

Thanks naetreb. Some very good ideas in your comment. May be I can cut a piece off of my old wind screen to use as a heat shield. It's made of aluminum, so it will be light, but still have to be careful with the balance.

Not sure if this will help with the simmer, but in the same vain with what MoapaPk was saying if the canister is warmer and fuller it'll help with the burn.

One thing I found with my Reactor (pretty much the same thing except MSR's model) was to make a cartridge insulator as well as a stove/pot insulator. My Reactor still doesn't really simmer wort a damn, but that's not really an issue because all i ever do is boil water in it. I bought one of those reflective windshield shun shades that's made of aluminized foam cells and cut it/gorilla taped it into shape. At night I take the canister in its cozy into my sleeping bag and that seems to work great. I believe there's a how to guide on Gear 30's website about making the canister cozy. As for the stove insulator it's just a tight fitting tube with a handle of the same stuff.

I bought one of those reflective windshield shun shades that's made of aluminized foam cells and cut it/gorilla taped it into shape.

That's an interesting concept although a canister jacket does not generate heat by itself. What I think it does do is to insulate the canister and keep the heat in longer after the canister is heated in the sleeping bag. Many times I have wrapped my hands around the canister and that has been enough to keep the fire going at a reasonable intensity. But, with a heat shield on the canister the heat from the hand would have a hard time getting to the canister.
I don't know, I may have to just breakout my old gas stove.

Yep, that's exactly what it does. I find it easier to handle in my sleeping bag (not just a cold hard lump of metal, especially if you kick it) and once warmed it helps to stay warm longer, though the cooling effect of the expanding gas does a number on the canister as soon as you start using it you do get some splashback from the stove heating the canister as well. On gear30 he even rigs up a copper heat sink to help cycle heat back t the canister, but I'm too chicken and too afraid it'll set the insulator on fire.

Copper heat sinks scare me because of a chance of canister exploding. Many years ago I rigged up this system for my winter gas stove, but never felt comfortable with it for the same reason.

Be careful with windscreens and canister stoves. Too much heat can cause explosions.

Jetboils aren't designed to simmer. It's mostly a small, light, and efficient on/off stove.