Svea 123R won't pressurize - what am I doing wrong?

Last year I purchased a brand new Svea 123R/Climber. In warmer weather it seems to work fine, but once you hit the low 30s, it gets a little more tricky. Last weekend I was out in 10-15 degree weather. I made a base to put underneath with some closed cell foam, cardboard, and foil, so it's insulated from the ground. If it primes well, it will start to make the sound I know it should when it's pressurizing. But once I put a pot on it, it will go to a fluttering burn, and eventually die. This happened to me after priming it three times with Coghlan's fire paste. Should I wait for the burner plate to heat up before putting a pot on top? I thought the pot would reflect heat down and help pressurize it but it just kept dying out. I was on an overnighter and spent almost all my fuel in the tank just to melt a couple liters of water from snow and boil a cup.

 

Hello pkz19, It sounds like your stove may not like the cold so to speak. Insulating it from the bottom is a good idea but is an important factor if you are using isobutane or propane cartridge stoves. A fuel stove like yours may need a second preheat if used in +10~15 deg temps. It sounds like the safety release valve (SRV) located in the fuel cap may be shrinking due to the cold or somehow unable to seal correctly when it works in warmer conditions. Also check the fuel cap seal, if it does not seal correctly, there is no pressure; these stoves are just over simplified carburetors and pressure is necessary, also a self catalytic affect is gained with some stoves when a pot is placed on top of the burner causing it to become slightly more efficient.
It also helps to use good quality fuel. Check back and post some photos so we can see your progress.

 

Hello pkz19

First of all, the tank lid must be without any leak! Check the gasket. Before priming, release tank lid and close it again in order to equalize air pressure inside and outside. Remember that fuel supply is made by the rising temperature of the air in the tank, which produces the necessary pressure. For the same reason, do not overfill the tank 20% of air is necessary.

Radler

 

Try fueling it up and dropping it into a pot of warm water. Bubbles should arise from any leak points. Also try cranking down on the cap, it may need to be tighter.

There have been some leaks from the stem and tank juncture of the stove, so look for bubbles there.

I love my Svea123Rs I think once you work this out it will be great for you too.

 

I agree with those suggesting a bad cap, either the gasket or safety valve. But if it is a new stove like you stated, and that is the problem, you really got unlucky.

However, first, you might ditch the paste and try it once priming with fuel, the paste generates a mild flame compared to a good dose of Coleman fuel. In cold weather, the tank has to get warm, it is not sufficient just to heat the burner.

And for warming the tank a little extra in cold weather, folks have been known to invert the (cold) stove, pour a small amount of fuel onto the bottom and burn it off to warm the tank. Turn the stove back right side up and prime as normal. It should not be necessary, but I have tried it and it does seem to work.

 

Like was said, you need to check for leaks. Stove should be basicly empty of fuel, stick it in bucket of warm water. This will pressurize the air inside, and any leak will show as bubbles. If you have it full of fuel this will not work as well.

I use mine all the time at 10F, it does take two primes usually. I trust the tip it clean?? If tip plugs it will get weak and go out. And a breeze is your enemy at that temp..

 

If you do a single prime when it is cold, you may want to keep the flame low until the stove gets hotter.
A dunk test in hot water is the best way to go. You can check it with the valve closed then test with the valve open. Open there should be a very clear flow of bubbles.

Has the stove been run until it was out of fuel? That can possibly burn the wick.

Ken in NC

 

All good tips. I have to add one though. My first backpacking stove was a 123R and after only a few uses I had problems like the OP is having. I tried about everything to make the stove work properly and it still would not pressurize or burn properly.

I finally found the problem and it was the burner jet was cracked, probably from over tightening. I replaced the jet and all was well.

 

As was indicated in previous posts here, it's important that the fuel cap gasket be pliable and the stove not be overfilled—four ounces of fuel in a six-ounce tank.

Always open then close the tank cap before priming and starting. This is a step that is only briefly mentioned in the instructions but I found it an essential step in getting my 123 to run well from the get-go every time, regardless of the temperature.

The coldest I operate my 123 is around 0ºF. I use a small, 4mm-thick acrylic board to insulate its base. If it's exposed to a breeze, I alway use a windshield made of aluminum foil two-thirds of the way around it but a couple of inches away from it, and usually prime it with Coleman Fuel with the pot on it, sooty as that might be sometimes. Below 20ºF, I always prime it twice. If the breeze is kept off it and the jet is clean it will run well. My experience with fire paste has not been satisfactory.

Putting a fiberglas rope wick in the priming cup and using meths for priming would work too but only if the meths were warm. At frigid air temp, alcohol is hard to light so the meths priming bottle should be kept where it can absorb some body heat. I use a fire stick for lighting.

 

Um
All the standard answers but the original poster doesnt have the standard problem. His 123r runs fine until he puts a pot on it. this should increase heat not reduce it

 

Very true, but, it also would be a good idea to do all the standard tests to eliminate the standard solutions.
He hasn't replied since the original post, is he still here?

Ken in NC

 

This seems to be the symptom of a too small burner opening, I recommend you check for partially blocked jet, maybe the internal cleaning needle is stuck in it ...

 

The pot part is a red herring. (unless there is snow on the bottom of the pot, I've done that)

 

Yes I am still here, sorry I was away on business for a few days.

I will try immersing the stove in warm water and report back on the results.

Somewhere I missed opening the tank cap each time before priming, so I'll be sure to do that from now on.

I have never run the stove dry, so the wick is fine. I suppose the jet could be clogged, though I don't I've run the stove enough for that to happen. I'll look into cleaning it.

 

I've run the 123 dry more than once, more than twice, with no effect on the wick or on the performance. I'm skeptical about the "run dry" issue. Certainly, I try to avoid it. But my guess is that "scorching" the wick is something that can happen in such a situation, but seldom does.

 

I cannot verify that running the stove dry does in fact scorch the wick. But I have replaced more than a few wicks that were scorched. I took the word of others.

Ken in NC

 

The problem may be as simple as this. If there's no air in the tank to pressurize you can certainly get the problem described.
Please let us know how you make out.

 

You have the 123R that has the built in cleaning needle so a blockage is less likely.
Good luck and Regards
John

 

I have used only a single Svea 123, and thus my experience is limited to that one.

I, too, hearken to the advice of others on the point. Accordingly, I strive to avoid the situation.

 

I have heard of users improving performance by removing the cleaning needle.
I don't own a 123R, only 123s.

Ken in NC