It was a new Svea 123 purchased a year ago that brought the stove pox. 12 months on it has some friends: The infectious stove is the one on the left and sports something of a novelty for a classic stove - a website address: Cute and all as it is, the performance of this stove has always been somewhat underwhelming. It will get the job done, but in its own sweet time. When the other two came along recently in quick succession (one as part of a Sigg tourist set, the other with what I think is the bottom half of an Optimus 88 set) I had a chance to compare new with old. Old wins hands down: All three were primed with ethanol and lit a few seconds apart. The new stove (left) actually had a longer priming burn by about 20s. The picture above is after they’ve been burning for about a minute. The new stove improves gradually over the course of several minutes but doesn’t get much beyond what passes for a simmer on the two older stoves: I’ve seen posts here that suggest newer 123s of non-Swedish manufacturer are no match for their predecessors. Is that what I’m seeing above? -R
I think this is the question, not whether "123" or "123R" is the correct name. Clearly "123" in the original refers to the 123R stoves pictured. I can't answer whether new 123R stoves can be convinced to seriously burn. Can someone else, please?
So if I'm reading this correctly the newest 123 R exemplar does not exceed the output level shown in the pic? That's interesting. For no other good reason than I wouldn't know what else to do first, for test purposes remove the self-pricker device and try again and see if there is any change in output. That stove would be a liability in the cold, a real tease, my finely calibrated eyeball indicates it may not even get a pot of water hot enough to boil. At best it would take a very long time. The newest stove doesn't throttle up, and the other two don't look to throttle down very well.
@IRM The conclusion I came to with my 123R was that a poorly-formed taper-threaded joint between the burner stem and the tank resulted in an air leak. That may be the case with yours, but you’ll not know unless you carry out a pressure test. @hikerduane recommends emptying the stove of fuel, putting it in a freezer for a half-hour (filler cap screwed down, regulator valve closed) then dunking it in hot water. The expansion of the air in the tank reveals air leaks. I’m assuming you tested the fuel cap and safety release valve seals? The only other cause of the low output would be a clogged/damaged wick. That could have happened if pump petrol has in the past been the fuel (additive deposits) or if the stove was regularly run dry of fuel and is carbonised in the burner tube. Thoroughly decarbonising the fuel passages in the burner (wire, compressed air) with the jet and pricker removed would be advantageous at the same time.
Thank you to everybody for their input. They are indeed all ‘R’ models. Removing the needle makes no real difference. The dunk test (overnight in the fridge rather a short spell in the freezer) showed no problem. I’ve had the stove from new, never burned it dry and never used petrol. The needle came out bright and shiny and I could see the teeth on the spindle gleaming down the vapouriser tube. The vapouriser looks to be a little better aligned than the one you covered in your thread: I fired it up again this evening. From a standing start it boiled 0.5l of water in a leisurely 7:20 or so. I put another half litre on after that which took about 6 mins. The flame after 7ish minutes was a bit more vigorous than yesterday’s photo, but still no match for the older stoves: For comparison, one of the older stoves boiled a half litre in 3 minutes from priming. I will look at swapping filler caps tomorrow, but I’m wondering if there’s something more fundamental at play like different materials with different abilities to conduct heat. -R
Interesting @IRM. Even Duane concedes the ‘dunk’ test doesn’t always reveal an air leak. The threads of your burner stem are very much ‘buried’ in the tank as are mine, which caused the fault I experienced. I don’t suppose you’d consider unscrewing the burner and re-inserting it with a smear of thread lock?
I might give it another go with hotter water. The last time was maybe a 50C difference which isn’t all that much given that the physics works in Kelvin. I’m game. I took a 71 apart last summer. I’ve a small vice, some padded vice jaws and can pad things further if needed. What thread lock would you suggest? I have some liquid PTFE which works up to 150C but I’m not sure that’s enough. That priming alcohol boils tells me that join gets at least half way there. -R
I use a medium-setting Loctite paste. I wouldn’t worry too much about the heat, the priming and subsequent firing won’t raise the temperature of the threads significantly above that of the fuel in the tank. The brass they’re encased in conducts the heat away. I’ve not found the thread lock to degrade over time, as in this Le Tiarko naptha stove burner.
Expensive stuff - upwards of £20 for a stick. I will have a go with the stuff I’ve got - hopefully this weekend. -R
@IRM That’s the price for the 19gm stick. A 9gm stick lasts for ages, but is worse value, granted, for a tenner.
@IRM re "I’ve seen posts here that suggest newer 123s of non-Swedish manufacturer are no match for their predecessors. Is that what I’m seeing above?" 123Rs... For finish, "quality of build" (quality control) this is an opinion shared here and i can see that. FWIW I too have held a curiosity re quality/type of Asian brass (more yellowish) ALTHOUGH if it is different, I don't see that as cause for any drop in performance. and Is it less/more resistant to dents... i see as an open question, I dunno. Noteworthy, 123R has been outsourced to Asia since mid-80s (to 2010s?) a looong time. It's been long enough that we might also consider early vs later Asian versions. Jus sayin'. ----------- I am curious are both your better performers stamped "made in Sweden" on top of tank? (only "Sweden", my impression, it's Asian). ---------- > Performance out of the box, on average for "made in Sweden" Optimus 123Rs... I can't recall performance problems with new, out of the box. > Performance out of the box, on average for Asian-made Optimus 123Rs... ("a lemon", assembled monday morning...) myself, i have no basis either way good/bad. That said GRANTED Asian "quality control" has been suspect so an "out of the box" concern may hold true, on-average. > Performance on average for Asian-made Optimus 123Rs, "user stoves". I see plenty of Asian-made that perform well. A performance difference vs predecessors, if any, is negligible is my take-away. ------------------ PS you made mention of the "WWW" thank you. I would respect *grumpy old collector that considers any stove with a bar code or a "www" is not a classic (until *we all die off). : )
Never used petrol? It’s a petrol stove! Unless you’re referring to automotive petrol. We have recently had folks on the forum attempting to use the 123 with paraffin. Basil
Several 123 users over the years have reported using unleaded automotive fuel almost exclusively with good results. It provides satisfactory performance, it isn't unsafe, or anything like that. I wouldn't do it unless I had to out on the trail, but it is a good data point to know. The problem though, unlike Naphtha, the additives included in auto gas blends will spoil in storage and residues turn to gum and varnish. No Bueno! This will ruin the wick, among other things. I suspect this process is slowed somewhat in a brass tank compared with steel, though I'm not sure on that. Automotive gasoline seems to attack brass floats in vintage carburetors and fuel tank sending units. I wouldn't hesitate to use it in a pinch, but would rinse it out or burn a tank of good ole Coleman fuel before putting it away.
>>What thread lock would you suggest? I have some liquid PTFE which works up to 150C but I’m not sure that’s enough. I've only been using thread locker on lanterns, but use the blue thread locker so I won't need to heat it to remove it. Personally, I will NOT use PTFE/Teflon tape again. Not that it doesn't work, but because it's so slick, you can easily drive the valve in too deep getting a snug fit, and also changing the clocking. Of course, you can counter this damage with thread locker, but know that you've damaged the threads so it will never be snug in its original position without a thread locker.
