Optimus No. 11 Explorer

14.5 ounces (includes stove and tool.  Fuel bottle and pump are an additional 6.9 ounces. Carrying sack adds 1.1 ounces) 

The Optimus Explorer is a white gas stove that uses a seperate fuel bottle instead of an integral fuel tank. It has a very nice windscreen which shields both the burner and priming cup. The priming cup also incorporates a wick, which makes priming somewhat easier than on the MSR whisperlight, although flare-up is still likely if you get too much gas in the priming cup. Because the priming cup is shielded by the windscreen, and because of the wick, the Explorer is easier to light in windy weather than other white gas stoves.

The Explorer simmers very well, and the pump pressurizes very efficiently, and doesn't require tons of pumping to get it going or keep it going. Overall, the Explorer is very well put together. The exceptions to this are: the "choke" which regulates air/fuel mixture, which is pretty cheesy and prone to falling off, but you only need the choke when burning alcohol for fuel, which I can't see myself doing very often with this stove.

The other part of the stove which I have had a problem with is a metal screen which slides onto the fuel intake tube inside the fuel bottle. This screen kept coming off and clanking around inside the fuel bottle. This problem was permanently fixed by crimping the screen down on the fuel tube with a vice. The stove's components are heavy duty metal, rather than plastic. The burner is solid brass, the pump is aluminum.

The Explorer supposedly burns just about any liquid fuel, but I've only ever used it with kerosene and white gas, (both worked well) and I mostly just use white gas. It puts out lots of heat, comparable to any other white gas stove I've used, including the MSR XGK which is renouwned for its heat output.  

One feature which I like very much is that the stove fits into my Trangia windscreen with the help of a ridiculously expensive ($15) adaptor bracket. When combined with the Trangia windscreen and cook kit, which blocks out wind extremely well, it makes a formidable stove for heavy duty snow melting and cooking in wind and nasty weather.

Like every other stove I've owned, the Explorer has its quirks and drawbacks. It has a long, stiff fuel hose, which makes it a tight squeeze inside when packing it inside a cook set. As a result, I tend to pack it outside the cook set. In order to turn the stove off, you have to flip the fuel bottle over. This prevents additional fuel from entering the fuel line, and when the fuel in the line is consumed, the stove goes out. You can also turn the stove off with the burner valve, which shuts it off immediately, but this leaves the fuel line full of un-burned gas, which leaks all over everything when the fuel line is disconnected.

Adjustment of the stove's flame is made with a small tool, as opposed to a flame adjustment lever attached to the stove as with most other stoves. I am always misplacing this tool, and have at times been forced to get out the pliers on my leatherman tool to adjust the flame, because I couldn't remember where I had set down the Explorer tool.

 On the plus side, this same tool is all that is needed for complete assembly and disassembly of the stove, so field maintenance is easy, provided that you haven't misplaced the tool. The Explorer is of pretty simple construction, and is easily field maintainable.

Overall, the Explorer is a very nice unit.  It simmers well, integrates into my Trangia windscreen/cookset which makes cooking very efficient, even in windy weather. In addition, I like the look and feel of the Explorer. The burner is made of brass, the pump is aluminum, not plastic, and it has a somewhat retro feel of quality and permanence about it.