Hello, A few weeks ago I was lucky enough to acquire a Primus 41 from a friend in Scandinavia (who found it at a local auction). She was pretty dinged up and tarnished , so I gave her a cleaning, swapped out the gasket and PIP with new equivalents cut from Viton while retaining the NRV's spring, brass cup and pump leather. I always take notes of their condition, parts missing, parts present, etc. At the time I received her the cleaning needle was present and protruding a few mm's above the jet (standard position when this stove is in the 'off' position). After the cleaning and swapping of seals she passed all the pressure-tests she was submitted to be deemed safe to run. She performed very well for the 10 minute test run, boiling water for tea and hot chocolate + testing her simmer settings. However, at the end of the 10 minutes, when I turned the spindle to increase the heat output (from a simmer position to high), the spindle would only turn a few degrees, as if something was jammed. So I turned it firmly and something obviously gave - the needle broke off. Because the fuel reaching the jet couldn't be stopped, she can no longer be turned off (or at least that's my assumption). To stop the flame I carefully unscrewed the fuel cap to release pressure and the stove went out. After she had cooled down, I removed all her fuel and unscrewed her jet and removed the needle. The needle, unfortunately, appears to be quite unique for shape/size. Not the same as an Optimus 111 and Hiker, Radius 43 and equivalents's needles. Now I have not tried swapping any non Primus 41 5-toothed needle into this stove - thought I'd ask the experts here for an opinion/advice who may have encountered this exact problem (short of finding a spare Primus 41 silent burner). I can still use her, but that just infers emptying her of any fuel when packed/portaging/not in use and during firing to not pressurize the stove until properly primed (fuel cap loose, no pumping). I've searched the site and come up with nothing that is of help. Thanks for any advice.
Hello SMolson. The cleaning needle rack has 2 parts to it including the needle, which is screwed separately into the rack.. If you look in the Stove Reference Library in the catalogue section under Primus, on page 2 on the bottom left corner is a reference to Primus Burner Nr.4155. There is a breakdown page of that burner showing the needle holder rack #1461(which you show) and the needle #4160 which screws into it. I'm not sure if the burner Nr.4155 is the same as yours but if it is, I think the part #4160(needle) may be hard to get. John
Hi John, Thank you, and yes it does look to be the same burner (although different spindle). If so, you are likely correct that I will be sol for some time. I will try to reset/replace the existing base (holder rack) to determine if there is a way it, by itself without the needle, can be positioned to shut the stove off and create a proper seal.
On another post I wrote: Smolson's silent 41's shut-off with the needle up. It looks like that may be the way with these - as with the 4155 burner. We know the roarers are conventional with 'off' & 'clean' at different ends. I have one I'm fettling & I can only shut it off with the needle up. No way can I get it to shut off with needle down. Anyone else got silent 41's who can confirm if needle-up is the shut-off position on these?
If I'm not mistaken(big "if"), the valve still functions to shut off fuel flow, not the cleaning needle. The critical difference in this design is that the needle carrier(rack) is installed on the opposite side of the valve spindle; so moves up rather than down when the valve is turned clockwise to close.
Abman47's perfectly right. The valve shuts the fuel off a fraction ahead of the needle projecting to its highest 'cleaning' position. So the cleaning needle is visible with the valve control wheel turned fully clockwise for 'off'. John
So my mystery problem disappears & I can complete my fettle! At last! Many thanks everyone! First time I've come across these reverse burners. SMolsons should also shut-off without the needle if adjusted right.
Thank you all for the help and information! It really didn't make sense that the needle would be used to close the fuel control valve. Although the needle on my 'carrier' did break off during the test run, the 'jam' I felt when turning the spindle was likely the carrier 'stuck' between teeth and perhaps slipped down or otherwise went out of position, which prevented the spindle from turning her full rotation to shut the fuel control valve. With both the needle and the jet removed from the stove and the spindle fully rotated CW, I pumped the tank to create pressure and there was no escaping air from the burner. Rotating the spindle CCW (opening the valve) air could be heard escaping. Good stuff. With the spindle back CW to the closed position, I resat the carrier (minus the needle) in the burner and screwed the jet back on. After pressurizing the tank I opened the valve and air escaped, but closing it (spindle CW) air could still be heard escaping. So the carrier must be jamming the spindle function again - either wasn't placed properly or she slipped down again. Anyway, the it doesn't have a needle anyway, so I removed the jet, took the carrier out, screwed the jet back on to a now 'carrier-less' burner. Pressure tested her and all is well. I test fired her, ran for 10 minutes (heating soup then boiled water for Bodem'ed Blue Mtn Coffee) and she runs great on all heat levels and turns off, phew. So she's back in business again. She's now adopted a spare Primus 4122 pricker (used on Primus 96) to clean the jet, as required. IT's a little tight between jet/top frame of burner but the pricker fits to clean it. I don't really like self-pricking stoves anyway ;>). Another issue with the Primus 41 - no 'emergency' pressure release valve on the fuel cap (same issue with the Radius 43's). Thanks again!
Two years ago Berniedawg, in this post: https://classiccampstoves.com/posts/141300 mentioned the odd needle position in the 4155 burner and suggested that a SVEA 1915 burner might make a superior substitute. The lack of an air release (so far) hasn't been a problem as the tank cap (so far) is easily opened to release pressure. Unfortunately the size of the cap seems to be unique as I had thought of substituting one from my other stoves but so far I haven't found one that fits. Another thing, the tank lid appears to be the same item as the pump rod cap (the latter drilled of course).They both appear quite "light" i.e. not of the same high quality as one finds on traditional (classic)Primus stoves.
Thanks Rob I'll take a look - I remember that now. The 4155 burner isn't the one on the 41 - it's the 4151 but I'm thinking it works the same way.
Done some delving & although all catalogues show the 41 silent with only 4151 burner listed - the 4151 & 4155 are the same except for the control - hinged on the 4151 & straight on the 4155.
My lack of elegance when trying to describe what I thought about the pump knob and the reserve cap needs clarification. What I meant to say was that both appear to be of pressed rather than machined brass. It is rather odd that Primus gave the 41 pressed rather than machined caps. I’ll try and find time this week and take some pix of my 41 and post them in the gallery.
Picture of the needle protruding from the jet (~1 mm ) See above link from Snowgoose clarifying the silent burners model numbers of the Primus 41.
