Hi all! I am having no end of trouble with a Svea 123R and I wonder if anyone has any pointers. By reputation the 123’s are simple and bomb proof, which is rather embarrassing! Symptoms: Difficulty getting up to pressure, requiring 3 or 4 primes with spirits. Yellow flame with lots of soot. Difficulty maintaining pressure (cutting out and surging). Generally not roaring as I know it should. Here is a video in case there are irregularities I can’t see. Things I have tried: New tank lid, from base-camp. The original had been a bit mauled, presumably by a previous owner attempting to service the pip. Have tried to check this for leaks, both by attempting to light any escaping fumes, and by blowing into the main tank opening to hear if it’s leaking air. Doesn’t seem to be. New wick, made from cotton mop head. I checked it for scorching after the first use. In testing without a burner bell, fuel squirts a couple of inches high after first prime, so I’m not convinced it’s a fuelling issue. Swapped the nipple for a known-working one. Replaced spindle packing and reversed the ring - a previous owner had run it with flat side towards the graphite packing. Primed 3 or 4 times in mild weather with minimal wind. All testing without a cleaning needle installed, to rule out cleaning needle issues. I did have trouble with shut-off. There is a bright ring where the spindle nose seals, but no groove. After cleaning and light polishing it now shuts off and seals fine. Things I can think of to try next: Different fuel. I’m using Upol S2002/5 ‘slow’ panel wipe. It burns cleanly with a blue flame in both manually pressured stoves I have (US M1950) and self-pressurising (Optimus 199). Is also 5x cheaper than Coleman Fuel where I am. Getting ‘hold of a pump to help diagnose leaks. The idea would be to bung the burner hole, gently pressurise the tank and spray it with a washing liquid solution to watch for bubbles. Otherwise, I’m completely out of ideas Any help to preserve my sanity would be very much appreciated!
first thing I would try is aspen4 or coleman fuel. Your upol information page doesnt have much info except two specific gravities and the slow is heavier and probably less volatile (slow dry)
1. Close your stove and put in freezer to cool down; 2. Then submerge in warm water to test for leaks. Fuel: Look at these two MSDS. The first, Shellite, is naphtha which is what your stove should be running on (ie Coleman fuel equivalent). Shellite is the perfect fuel (in Australia) for gasoline stoves. The second is for the fuel you are using. Check the critical factors such as boiling point etc. https://diggersaustralia.com.au/wp-content/uploads/sds/Shellite NZ v6.pdf https://u-pol.com/wp-content/uploads/S2002-5-SDS.pdf Edit: crossed with @snwcmpr Tony
Meaning, you didn’t use the mini-pump to pressurise it? I too suspect the fuel. Without pre-pressurising the Opt 199 with a mini-pump, its larger burner and consequent mass of metal coupled with a much greater priming cup capacity most likely led to more heat conducted to fuel that in the 123R was insufficiently volatile to adequately self-pressurise.
Thank you everyone for your help! @geeves @Tony Press those data sheets are particularly insightful. It didn’t even occur to me to check, but it makes perfect sense. Looks the ‘slow’ UPol sits between paraffin/kerosene and naphtha for boiling point and range. I have procured some Aspen 4 (boiling point 36 rather than 140ish!) which I’m hoping will do the trick, and if not I’ll attempt a dunk test. @presscall something of a Freudian slip - I have a 99 not a 199 However I recently acquired a modified Shmel burner bell and caps for it, which would still match with your prognosis. Will try it with Aspen 4 too - I suspect it will work even better! I will start another thread for the tangent, but I have been wondering if the 199 windshield could be modified to work with the Shmel burner. Probably easier than finding an actual 199! Thanks again.
