I wonder if any of you learned people could help me.

My partner has bought us a rather nice Primus Himalaya Multi Fuel Stove which offers us great versatility. The problem we are having is that when we run it on parafin (kerosene) it flares after a few minutes of starting. The stove starts well enough, bursting into life with avengeance, but within 2-3 minutes the flaring starts.

It seems fine with petrol, Coleman fuel, and Propane / Butane gas cannisters, but as it's more probable that we'll be using parafin when backpacking I'd like to get the problem sorted. We've tried priming for longer (MUCH longer sometimes) but to no avail. Using a windshield doesn't make much difference.

What strikes me as odd is that I would expect the stove to run with perhaps a little flaring when first started, but as it heats up, any flaring should subside. As it is, the opposite happens.

Any ideas?

Many thanks,

John

Hi,

Perhaps, it will help to check if the jet is the correct one. I own an Omnifuel, I know I have to use the jet with the .28 stamped on it for kerosene.

.45 for canister gas; .37 for gasoline; and .28 for kerosense and diesel.

If you are already using .28 jet, I have no idea why it is happening. Maybe the jet is stamped with a wrong number.

Since the proper jet for kerosene has the smallest hole of the three, it may be as simple as looking through it against a light, in order to make sure the jet you use has the smallest opening.

Hi John,

I have both a Varifuel and a Multifuel. The Varifuel is mounted in a Trangia adapter and seems fine with kerosene. I haven't tried the Multifuel with kero because the instructions don't recommend it in the version I have. There are some small differences with the burner cup, which should allow more air in.

I will try and reproduce the problem if you like. Can I check which jet you are using, exact timing on when the problem occurs, whether you are running the stove wide-open at the time.

I did once run the stove having reassembled it without the wire cable which should be inside the generator, and it behaved pretty oddly...

Hello,
I wonder if the burner is not hot enough. You state that after two mins of operation the stove flares up. Does it do this for just a short time?

Most of the brass stoves I have will ignite into a blue flame after pre-heating. I usually give the stove one pump to start the ignition of the kero. If I apply more pressure before the burner is hot enough the fuel comes out as a liquid and not a vapor. This results in a flare up and then it dies down only to flare up and die back down in smaller increments until the burner is heated sufficiently to vaporise all the fuel.

Try letting the stove run for a bit before pumping the tank. Or you could double prime which envoles primming twice so the burner is really hot.

Hope I was of some help.

Chuck

Many thanks for your advice folks, but this dammed thing still flares!

I've checked the jet, it's correct at 0.28.

I've primed for up to 5 minutes. The stove seems to start OK, after leaving it for around 3 minutes the flaring starts, even at fairly low flame settings. I've experimented with different settings / times from starting to opening it up, but it's still the same. I don't think it's ever been run at full bore.

I've cleaned the stove meticulously.

I've checked the quality of the parafin by using it in two other stoves (a Nova and an old brass Primus) with no problems.

Perhaps the generator is suspect. Although it's position looks right compared to the picture on the box, when it's running I would have expected the flame to play on the generator a little more to help vapourise the fuel. If it doesn't get hot enough whilst running it isn't going to be too happy running on a low volatility fuel like parafin.

Hrmph.

Any more ideas folks?

John

I have the MF and so far I've not have any problems with
kerosene fuel.

I don't know what exactly to sugest other than check your generator and check to see if your fuel flow is not fluctuating.

The other fules you mentioned that you tried are quite a bit less dense than kero. Hense they flow better.

You can check the seals on your fuel pipes, as well as your gererator, and check if you have some gunk cloging up the works and remove the gunk.

I found that the generator on the MF is rather small internaly) when comparied to other kero capable stoves.

I practicaly never us my P MF I use a Nova now.

Thank You

yt

NorthernFlame

Thanks for your advice.

I've removed the wire from the generator and cleaned it, but it wasn't at all dirty. The seals seem OK, well nothing leaks. Everything else has been cleaned, but as the stove hasn't been used that much it hasn't really got dirty. (I haven't got a lot of confidence in it as it is). Unless there's a manufacturing fault I'm stumped!

Interesting that you've got a Nova, I bought one yesterday after reading so many glowing reports. I must say, although it's only been used in the back garden for testing out, I'm very impressed....dead easy to prime with parafin, and a very good flame control. I think this is the stove I'm taking on my next trip (2 weeks in Scotland in May).

Perhaps I should send the stove back to the manufacturer for them to check out.

Although I'm not the most experienced parafin stove user in the world, I have been using them on and off for 30 years so I have more than a little knowledge, but not much more. You people on this site are SERIOUSLY knowledgeable!

Thanks for your help,

Cheers,

John

Hi john

As a matter of course flare ups are usualy casued by either

A: Over presure (over heat)
B: Air pockets

Normaly kero flareups occur in the compact camp stoves
such as the optimus silent burner stoves. But you can ask others about that.

I got my MF as a gift. It's promotion has obviously been over rated. It's why I went for a Nova instead. As my camping stove of choice aside from the usual alcohol stove.

As others have replied as well. I find is odd that your MF flares up after 5 mins or so. It's almost as if something has over heated and expanded or constricted the flow of fuel . Probably somewhere near the generator.

Try running your MF is a cooled area with some breeze to help cool the stove. Then time the time it takes to
start flaring up. If the time interval get's longer than your claimed 5 mins then you know there's something over heating.

That's all I can sugest for the moment.

Enjoy.

Hi again.

One point. Depending on your point of view you should note that this stove seems to have been tested in very cold high altitude climated . Hense the name "Himalaya".

Technicaly it's souldn't matter as the fuel supply is far
away from the actual burner.

However in my experience most camp stoves have not been tested is every climate around the world (unless by regular people like here on spiritburner). It's simply too costly to send out stoves to be tested in every climate.

It would be like proof testing if a gassoline stove could work in a hot desert . Sweedish Hand grenade for real.

Thanks for the chat.

I have the Varifuel. Mine pulses & flares quite violently sometimes - the flames jumps about 2 inches. It's almost like a strobe effect. Eventually I put it down to overpressure as it eases off if you flip the bottle for a while. The stove is now redundant. A Nova has taken over for the times I would have used it.

My early MSR pre-GK multifuel has a sintered bronze filter under the jet to suppress surging - since disappeared in more recent designs.
The Dragonfly and Nova both have fuel filters in the line - I've wondered whether these serve a double purpose.
On some stoves I believe surging can be prevented by inserting a control cock in the fuel line.
I don't understand the mechanism - if anybody can explain I'd be interested.

Well I've not given up, but I have admitted defeat.

I've emailed Primus with the problem to see if they can help and also to see if they have a service agent in UK who can check / repair or whatever. I've spoken to them before, but there only suggestion was to increase the priming time.

I'll report back with their response.

Cheers,

John

Hay John
is there any flame at any time from around the jet oriface. If so you have a leak there. This will great problems like you have also will cause soot and smoke. I wont explain why here on this site because it will take too long.
You can send me an email at the above if you wish so we can go into more detail.


Handi Albert

I don't think there is, but I'll fire it up again and check. It probably won't be for a couple of days because I won't get home from work until late.

Thanks for your input!

Cheers,

John

Hi,
I've checked, but there appears to be no flame around the orifice, only from the spreader. Another idea bites the dust!

I haven't had a reply from Primus yet, but it's too soon yet, I only emailed them yesterday.

Thanks for your input!

Cheers,

John

Ok John.
Have you put a blow torch on the burner tubes while the stove is running. Try this and what happens.
I still think it is a better idea to contact me direct

Handi Albert

I concur with the air pocket theory. I own two Varifuel stoves and neither one have this problem. Hottest stoves I own. Similar to what Ross interjected, they do strobe a bit at first but this soon dissipates. Since pressure originates in the fuel bottle, I would inspect the entire fuel pump assembly, seals, etc. Swap it out if at all possible. Hence the air pockets.

Albert and I have been corresponding directly by email on this persistent problem, but I thought I'd add this update:

I took Albert's advice and played a blowlamp onto the generator tube which seems to help:

I started the stove in the usual manner, with around 3 minutes of priming. The stove burst into life, but as before, it started to flare after around 2 minutes.

I then directed the (gas) blowlamp flame onto the generator tube, after 30-40 seconds the flaring stopped. Great! I took the flame away.....and after about 2 minutes it started flaring again.

I've obtained a new jet (0.28), kindly sent by the UK Primus importer. I tried this without, and then with the blowlamp treatment but got the same flaring.

What I neglected to mention to Albert in my last email to him was that the generator tube got VERY hot with the blowlamp treatment, even starting to glow. At that point I decided thing were getting silly.

The next step is to try a different brand of parafin, but I'm not too hopeful as I've used this parafing in two other multifuel and one parafin only stove with no problem. Before I change the type of parafin I'll completely strip and clean the stove again.

Perhaps I'll by a Trangia.

Cheers all,

John

Can any one tell me if the jet from a #1 or 5 primus fits the Primus Himalaya Multi fuel stove.
If so I will send John a jet to try
Albert

Hi Albert - unfortunately it's a lot fatter than the old jets