User Review: Primus Gravity MF
Price Paid: $105
New to the liquid fuel stove arena, I purchased this stove to take to Argentina to go backpacking. I chose it because it was lighter than most, I like Primus brand stoves, and because I knew I would have to look for an alternative to white gas. All the travel books I bought said to look for "solvente" to burn, so I did. White gas is not available and this stove was billed to burn either white gas or kerosene. I was told -- as best as I could understand -- that "solvente" was the closest thing to it. I quickly learned that solvente was nothing more nor less than paint thinner. I tried it and the stove burned fine.
However, after three days on the trail one very cold morning the stove did not burn fine. It burned very choppily. After some prodding and clearing out the jet using the included tool, it burned again for another couple of days and then again began to get very iffy.
After the trip was over, I learned from the park rangers that a) they all routinely clean their stoves at least every 10 usages completely including the cable inside the hose if using solvente; b) they use LIGHTER FLUID instead of paint thinner (I was so over-focused on the travel guide I never even thought of that); and c) you really need to go through the exercise of completely dismantling your stove if you are going to go on a backpacking trip in a remote place and perhaps have some extra, extra spare parts i.e. o-rings.
Once I cleaned out the stove completely, took it ALL apart and ran a pipe cleaner through the hose and took out the cable, it again burned brilliantly.
For what it's worth, my hiking buddy has an MSR Dragonfly that burns petroleum fuels, and it was never ever able to burn paint thinner, not even once, but the Gravity MF absolutely worked with it although I doubt "paint thinner" is on the approved/recommended fuel list.
So, the whole point of the fuel story illustrates that the stove is certainly well designed, but requires some constant maintenance if you are going to use non-standard fuels. I have seen on REI a maintenance kit that included extra jet nozzles for an even wider variety of possible fuels. I would add pipe-cleaners to the maintenance kit...
Now, one interesting part of the design is a lower than average profile. This proved to be very useful in the constant winds we experienced. Using the included wind foil and foil stand, the stove worked great.
If I were to take this stove with me again on a future cool/cold weather trip, I would do the following: 1) store the stove inside my tent during the night to prevent the stove from becoming too cold or damp, which exacerbates the burning problem (if there is one); 2) spring for lighter fluid instead of paint thinner if I cannot bring white gas (you gotta love it, though... paint thinner...); 3) remember to lubricate the o-ring prior to each use; 4) make sure I have extra o-rings.
On short trips or in warmer climes, I would go with a "baby-stove" that goes on a canister. But if you can only justify owning one stove and want an optimum combination of lightweight versatility, get it. I would have to say once you know how to thoroughly take it apart and clean it, it seems very, very reliable even when using dire fuel sources like paint thinner. If I had been able to make it through the whole trip without taking my brand new stove apart -- paint thinner or not -- I would have given it five stars.