Some stoves require just a little maintenance to keep them operating optimally. Liquid or multi-fuel stoves often feature a generator loop where liquid fuel is vaporised. This occasionally requires internal carbon deposits removing. It isn’t a difficult task if carried out before it becomes a problem.

Amongst the most common problems encountered with liquid fuel, dual-fuel and multi-fuel stoves are dirty fuel lines and clogged fuel jets. Some stoves, such as the MSR WhisperLite Universal, have a cleaning wire cable in the fuel line. Packing my Edelrid Hexon multi-fuel stove away for the year, until again unearthed next winter, I took a few minutes to give the generator loop a bit of a clean.

This is a simple job and made all the more simple by dint of two things. Using the cleanest fuel possible, and cleaning the stove frequently. I complete this task before and after every outing with the Edelrid Hexon, leaving little opportunity for carbon deposits to become built up. This is far more frequent than many owners might carry this out but if done often, even on trail, it is a quick and simple task and pre-empts problems. My fuel of choice is either gas or Aspen 4. Because this fuel contains no unsaturated hydrocarbons there is no build up of resins in the stove jet or fuel hose. While it is a fossil fuel, it is a far cleaner fuel than standard petrol from the pump.

Most multi-fuel stoves have dedicated repair tools and service kits and the Edelrid Hexon is no exception. It has a small multi-tool that includes just about all that is required to complete an almost full strip and assembly. This includes removal of the thin cleaning cable inside the generator loop. The multi-tool has the correct 8mm open end spanner/wrench to tweak and unscrew the brass connector attaching the fuel line to the generator loop that passes over the burner head. It is inside this loop that liquid fuel is vaporised, hence this is where most deposits will be found. This is a cleaner job if completed while the fuel line and generator are dry but if considerable deposits have built up inside, fuel can be pushed through the fuel line under pressure from the fuel bottle to lubricate the cable while stripping down. This will also make it a muckier job.

Once the fuel line is removed the cleaning cable can be seen poking out of the generator. The cable is removed by using the small hole at the end of the multi-tool. The end of the cable is inserted into the hole, the tool twisted slightly, and the cable pulled out. Pliers could be used if particularly stubborn, however only the welded tip of the cable should be gripped to avoid fraying the cable. If it simply will not budge, try spraying WD40 into it, or leaving it to soak in this for a few hours. Pump cup oil can be used instead, dribbled down inside while held vertical.

Remove the cable and wipe off any carbon deposits with a paper towel or lint free cloth before replacing the cable and working it in and out to remove any further internal deposits. The cable is then cleaned off again on a paper towel or cloth. The cleaning cable remains darkened but loose deposits will have been removed. Once the cable is returned, leaving about 5-10mm protruding, the stove is reassembled. When reinserting the cable, the curvature in the cable is kept aligned with the orientation of the curve of the generator loop.

The jet may require cleaning or clearing too. The Hexon multi-tool has a pricker for this, as do the dedicated tools for many other multi-fuel stoves. Some stoves may have shaker jet or magnetic jet cleaner technology instead. The fuel line itself is seldom affected by internal deposits, but allowing a little fuel to be flushed through this under pressure while the generator loop is disconnected can clear some debris if present. If the fuel is caught in a container this can be used to soak the generator cable in prior to wiping clean. This fuel must be disposed and not reused.