Hello! After my first adventure with an Optimus Hunter 8R ... Link ... I thought I could try another one. I got this Primus 71 from a local online marketplace. From the pictures it looked to be in good condition, little wear on the box but it appears to be sprayed over. There's even some paint on the stove. Anyway, that's not such a problem, that goes off easily. I tried it and it doesn't fire up. With the cap from my 8R, it builds up pressure (when I unscrew the cap after trying, I hear 'pfffffff'), but it doesn't fire up. I removed the cap and it looks like the burner jet is clogged. I can't get the needle in it (only a tiny bit). What would be the best approach to repair this? It looks like I can't unscrew the burner head and jet like on the 8R or 123R's? Also, the regulator rotates very loosely, and there's about 5mm distance between fully open and fully closed, is that normal? Final question, the text 'AT' on the bottom of the tank, does that indicate a date or something? Thanks, Ted Open Closed
Small update: it's burning now Removed the burner assembly (now with a vice). Had a look at the wick - very green - and I get green drops in the white coleman fuel. Tried picking through the jet again and now got through. Assembled again and got it working. Oddly I needed to keep my lighter to the head for a while after it was pressurized. The burner was emitting plenty of gas but couldn't keep itself burning after I removed the lighter. That effect was gone after 30 seconds or so. It burned for a while, not as hard as my 8R but a reasonable burn. I would like to know how I can clean the insides of the burner assembly. Perhaps some solvent? The wick looked OK, apart from it being green. Can this wick be replaced? It looks a lot thicker then the wick in my 8R? It appeared to be stuck also, I couldn't get any movement in it. Thanks, Ted
More update, found the diagram on the Primus 71 in the gallery. Looks like the head and burner can be removed, the wick as well. My wick was enclosed in a tube that went almost to the bottom of the tank, it doesn't look like the one the diagram below. Is that normal? (sorry took no pic of the wick)
Hi Ted, You should try to remove the jet and give it a thorough clean, so that you can see light in the hole if you hold it in front of you. Typically there's crud accumulating on the bottom inside of jets. Make sure you replace the tank cap seal. Don't worry about the length of the fuel pickup tube - it will work at whatever length. If the spindle turns loosely, you can carefully tighten the locking nut. After some 10 minutes of burning clean fuel, your stove should burn fine. If it doesn't, you should think of replacing the wick. A strand from a cotton floor mop works well. Post some flame shots! Enjoy! Yonadav
The 5mm movement you described is merely "Free play" When you get the stove burning properly you will note that "off" to "full on" is a much smaller distance. As Yonadav said, if the spindle is loose or leaks, simply tighten the packing nut a little at a time until it tightens up. You don't want it too tight. I have several Primus 71's and Optimus 80's, they're good little stoves. And it's a really good idea to replace the fill cap gasket. Look in "The Fettlebox" on the right margin of your screen. Gerry
Thanks all. I got the wick out (top is pretty charred) and replaced it with the better looking one from my old Hunter. Again had a problem with the stove. Had a look at the wire that hold the original wick, and there's a little empty loop at the top that keeps the top of the fuel jet free I assume. I'm now again unable to prick the jet so I probably pushed the wick to far up. I'll redo it later today. I'll also get a new gasket. The old one rock was hard and brittle. For now I'm using the cap of my 8R which has a new gasket. One question, can I remove the burner cup? It looks to be a press fit or something? Thanks for the help Ted
Correction, had a more closer look and the wick can't get up to the fuel nozzle. It goes to the side of it.
Got the burner head off as well, and the nozzle - everything is now cleaned. Waiting for the materials for a new wick.
Sounds like you are having a grand time with this stove. Good thread to follow, and you did great on the photos. A 100% cotton mop string works very well for a wick. Ken in NC
I love my 71--it's in my backpack right now. Other than changing the cap gasket (what a difference!) mine has worked wonderfully for years. Watching thread with interest. Keith
Update: Replaced the wick with three strings of mop cotton, and it burns very good now. There is still some behavior which I don't really get. When I've preheated it, and open the valve, I get a pretty good burn, but there is a very faint hiss, which sounds like some gas coming out the stove which doesn't burn ??? The stove is not leaking, I checked it under water before and there are no flames near the gaskets or fuel cap when I put a flame near them. It looks like more gas is coming out of the head then the stove is able to burn. Does that make any sense? When I open the valve more, it burns less, and doesn't get to the harder burn anymore. When I leave it open wide it dies and all the pressure appears to be gone and it doesn't fire anymore. So I tried again when it was cooled down. Again pre-heated, fired it, got a pretty good burn, set a pot on top of the tin, and let is sit for a while. After a few minutes, the stove went into overdrive, the hiss was gone, and it was burning at full power. Got 500ml to boil in less then 5 minutes, which is as good or better then my Hunter 8R. I now could open the valve even more without it dying. I put another pot on it with cold water and let it work again. When I fiddle with the regulator, like simmer it a bit and then open up again, it sometimes goes back to less then full power and then after a while jumps into overdrive again. Is this normal behavior for this stove? Can't remember that from my Hunter 8R (my new one and from the old days). Once it was at full speed it never went down. The sun is going down so in a couple of hours I'll post some flame pics (they look better when its dark).
Forgive my lack of knowledge, but is is possible yours has a cleaning needle?? (an R model) if so, it will shut fuel off when opened all the way up, like your 8r should do. Keith
Hi, there is no cleaning needle. Don't think the Primus 71 or Optimus 80 were ever made with a cleaning needle. The Svea 123 is similair to the 71/80 if I understand correctly, and the 123R has a cleaning needle, same as the Hunter 8R.
Some pics, shot inside. Tried it out first outside but it for sure doesn't like the wind. The flames stay blue, with a tiny faint yellow tip at full power. And a video: http://youtu.be/styuuDbnMvc One more question, does this model use a graphite packing on the regulator and stuffing box like the 8R and 123R? I can't find any documentation on that. Thanks, Ted
Yes, there is graphite packing on the spindle. Your stove is burning very well. The inconsistent power you mention could be caused by pieces of crud that set loose around the valve and get stuck in the jet. Another possibility is a few drops of water in the tank.
Hi, The graphite packing for the 80/71/123 (early model svea) is Optimus part no 2091, you can order this from Mike @ Base camp (This sites sponsors). Replacement of this part is normally a rare event, with the 8mm hex head stuffing box removed, the valve needle will unscrew leaving the graphite packing intact & undamaged, it's highly unlikely that you will have to replace one. If yours has the 19mm filler cap thread, you can use the mini pump (part no 2091) which will improve the performance of your stove quite markedly, best wishes=John. --------------------- If in doubt, brew up.
Thanks for the info on the packing. I'll leave it as is at the moment. I got my (new) mini pump and cap yesterday evening which I ordered a week or two ago from A&H (Packstoves). Just curious, are these still made by Optimus or is someone else making them? I understand these are different from the orignal smaller one and the angled one. When I give the tank 8 pumps before priming, let it prime, and the light it up, it goes to full power straight away. Works great. Both my 8R and 71 now boil 500ml of cold tap water in less then 4 minutes. Now I need to start working on the tin. That will be some work to get that clean.
