I had a new (to me) stove delivered yesterday, an Optimus 8R that looks to have had a very hard life. The case only has a little of its original paint left, with a coating of burnt matt black paint instead. What it was run on I don't know, but it smells disgusting. To my nose the whole thing smells a sort of burnt old engine oil smell, not nice. There was a thick black coating over the jet and burner (and inside as I found out later). At first I wondered about whether it was an Optimus or a clone but looking at pictures on here of other Optimus 8s I now fairly sure it is genuine. It has no markings at all, anywhere, the flame adjuster is the red bakelite one but that doesn't mention Optimus and only has the words clean and close on it. I took some pictures and I'll put them up when I get a chance. I gave it a quick once over and dug out the panel wipe to see if it would fire up without any work. At first it would only give a very weak flame, so out came the tools. I've been reading up on the 8 from various posts on here, so I headed straight for the wick. This had been charred, so I took it apart and got rid of the charred sections. I dismantled and cleaned the rest of the burner assembly, the control valve was all caked in a black something. Once cleaned and re-assembled it fired up and gave a fairly strong flame, but not quite like the pictures I've seen on here, so I think it may still be a bit blocked. When I got my 00 I had to heat and quench my burner to unblock it. Is it safe to do this with the 8 valve body? I'm thinking that doing this might burn out any crud left in there, but I don't want to trash the valve body in the process. After it had been running for a while I started getting a bit nervous about how hot the tank gets on one of these. I stuck some masking tape on bits of the tank and dug out my non contact thermometer, and found that most of the tank was at 60C and getting warmer. Just how hot is safe for the tank? I like this stove a lot and I'm looking forward to getting it working perfectly. Once it's going strong I'll strip it and clean the outside properly and give the tin a nice new coat of paint. Simon.
I don't have much experience with the 8 (8R in my case), and you will surely get more helpful replies from other members, but for what it's worth: - 60C seems quite hot to me, and I would expect a real good pressure build up and a correspondingly powerful flame. - Probably a silly question, but the stove has got a heat shield properly installed so that there's a suitable air gap (5mm or thereabout?) between the shield and the tank? - Besides a partially blocked burner, a slight leak from the fuel cap would reduce the pressure and hence the output a lot. Have you checked the gasket? I absolutely agree that the 8 is a nice stove - open the case and go! Knut
You say 60C seems hot to you, is it too hot? I've no experience of these stoves so I have no idea what is a safe running temperature for them. No such thing as a stupid question Yes it does have the heat shield fitted. As part of the cleaning up process I made up a new gasket for the filler cap as the original had gone hard. Can anything be done with the pressure relief valve in the cap, perhaps the seal in there may be leaking? I didn't want to touch it in case I messed up some factory setting. Thanks Knut, Simon.
If I could answer those qusetions, I would be happy to do so The tank of my 8R doesn't reach 60C, but then again I would like it to burn a bit hotter. I would guess my Svea 123R (bought new) reaches a temperature in that range. I have never measured, but it's definitely too hot to touch for more than a second or so. And the Svea boils a liter of water in 7-8 minutes, so assume that one operates at full power. I have wondered about the safety valve as well. My impression is that if it has blown, it will leak to such an extend that the stove is unusable, but I assume it could "almost reset", ie. have a very slight leak, but still make it possible to operate the stove at reduced power. I haven't read/heard about safety valves starting to leak without blowing first, but that doesn't mean anything really. The general attitude seem to be - leave it alone, don't touch it. Which of course is good advice when it comes to any safety device unless you happen to know what you're doing, but it would be interesting to know a bit more about them. Other leakages could be possibe as well I suppose; the burner/tank threaded coupling, around the valve spindle (tends to be a flame there though), and possibly even the tank itself. If you have a cap designed for a mini/midi pump, there would be a no return valve as well... The trouble with these stoves is that - unless you have a mini/midi pump - there's no easy way to pressurize an unlit stove in order to check for leakages with soapy water or similar. Knut
Thats' reassuring and sounds just a bit hotter than 60C to me. Is the 8 burner comparable to the 123? I boiled about 500ml of water in an open crusader mug in around 7 minutes last night and I was hoping it would perform a bit better than that. Ta, Simon.
If you want to do a heat & quench on your #8 burner, then you need to disassemble it completely. Remove the jet, the spindle, the graphite packing , the cleaning needle, everything. Strip it back to the bare bones, then heat & quench to remove any gunk in there. You say that you've snipped some charred ends off the wick. Any chance that you have removed too much? That wick needs to be a certain length, might be a good idea to just make a new one from some mop head cotton.
Excellent, I'll roast the burner tonight then. I did trim the wick but there is still plenty left in the fuel, but I will be making up a new one as well sometime soon. Thanks, Simon.
