Primus Gravity MF
Price Paid: $75
The Primus Gravity MF appeals more on paper than in use. The combination of a wide selection of useable fuels and light weight sounds great in principle, but in practice the promise is not delivered.
The stove is lightweight. It is also flimsy and assembled from too many fiddly components which offer doubtful durability. Being able to use gas canisters and liquid fuels is an attractive feature, but the jet removal process is tiresome and not recommended.
I've used most modern stoves over the last thirty years and can say that the Primus has the complexity/vulnerabilities of the early dodgy MSR WhisperLites; the pump in particular is over-engineered.
After only a few uses I had a small fall coming off the Ballow Range in bad weather. The only item of gear (or me!) that was damaged was the Primus which immediately stopped working. Worse there was no discernible damage that indicated the problem. When it worked the flame was variable and didn't simmer readily.
Not recommended, especially for long walks.
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.
Overall great product! I used this when I was guiding in northern Ontario.
For starters, Primus has a great idea by including a metal pump with the stove. As much as MSR stoves are great, I never really liked the idea of having a plastic pump. Next I really like the length of the hose. It keeps the fuel bottle just a bit farther away then most keeping it out of the way.
I have used it with both white gas, and LP gas. They also have a very simple set up making it very easy to switch the inner pieces to change the try of gas. Also because the stove comes apart simply, it makes it easy to clean. It has a low center of gravity, and a 4th leg making it more stable with pots on top of it. It is also small enough to fit inside a small pot, and very light.
Price Paid: $121.99 $Ca
Bought this stove as my trusty Coleman Apex II's pump died and we were heading out right away. Used it in White gas mode.
I like the low profile of the stove and the 4 legs. Very stable. It held a 3L MSR pot with no wobble.
Lighting is as advertised and works well.
Easy to use, Light weight. The metal pump assembly set at an angle,(my Coleman 's pump crapped out with a plastic disc behind the pump diaphram breaking), I like turning the pump and bottle over to burn off the fuel in the stove line.
Fittings to gas line and stove are A1.
I really don't feel the stove really puts out the BTUs. (seat of the pants, I didn't measure boil times) Used at 4900' mostly in windy conditions. I felt I had to use the windscreen ever time regardless of wind.
Simmer is touchy. It only seems to burn out of one side of the burner(when trying to simmer) and it went out a lot.Big disappointment!
I don't really have a feel for fuel usage as we used it for 5 days using 1.5L for 3 people.
The stove came with a DVD but didn't show the MF just the Omni fuel or multi fuel. In the DVD they mention the jet (for omni), installed is for white gas. NOT SO for the MF!!!!! Why include a DVD with no MF video?
It came with the LP jet and I had to change it out after I read the instructions,watched the DVD, went to the website to double check and then took the burner apart to see which jet was OEM. This is Canada and I may be wrong but White gas seems to be the most prevalent fuel.the Dealer didn't tell me, (I will be talking to them) or didn't know to tell me.
The tool supplied to change out the jet and to clean it has a small flat screw driver end that is too small to undo the top screw on the burner to access the jet without messing the slot on the screw, WTF!!!
I have the Gravity MF but the website shows the Gravity II MF. Did I get the latest model or did we in NA get stuck with old stock? (the dealer had a lot of them)
2.5 stars as I don't think this stove is better than my old Apex II which is 10 yrs old.
If I could get to to simmer it would be a 3.5 star.
At first, sorry for my bad English...
Great stove, but the flare is not uniform. I have bought a Gravity MF several days ago, and I just use it with LP gas, never with liqulid fuel.
The stove is lightweight, stable, very good output, but the flare is not very uniform, the flare at one side of the burner is very big, and the other side it smaller...especially when I turn the flare to very small...
Look these pictures:
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