Hi all. A question for the more experienced here. I finally got around to cleaning up my 8r this winter, as I'd like to use it on a few canoe trips this summer. All the rubber bits are replaced, as well as the wick. However after running through a few tankfuls, I've noticed that the pot stands get quite sooty. I haven't seen this on any other stove that I have. Any idea what could be causing this? Jet needs replacement? Thanks Tim
This is quite normal, nothing wrong. The pot stands are not radial on a Optimus 8, but are crossing the hot gas-stream. This creates a turbulence in which some places get cut off from the oxygen of the air. A part of the carbon in the fuel can't burn and is left as soot. Best regards Radler
If you look at the first picture, you see all four flame-parts are crossed by the pot supports. You could try to turn the flame plate a bit to make two flame-parts flowing parallel to the supports. These may reduce soot. Radler
My 8R doesn't soot like that. It also burns completely blue, no orange tips like you're starting to get. I would say my flame is somewhat smaller as well. My other stoves don't soot pot supports when the flame touches them either. If you're burning any even slightly questionable fuel, drain it and put in clean fresh white gas. Give it a bloody good gallop for a couple tanks and see it that helps. If not, yes look at the jet.
As non of my 8rs actually work I'm afraid I'm unable to comment from experience, but it does sound like it's running on the rich side.
@Simes The pan is an important part of the setting. The gas-streams are quite different with a pan. Most roarer burner flames are a bit yellowish, when operated without. The inner part of the flame gets less oxygen. You also can see the flame plate is getting red glowing (~600°C) without pan, quite different to the situation with pan. Radler
Make sure your fuel is clean and hasn't got a little kero mixed in inadvertently or any sorts of oil in the tank. Flush tank with clean fuel or brake cleaner which works for me. Check to make sure your nipple orifice isn't overly large. (no larger than say 0.33 / 0.34 mm). IMHO also your flame spreader is sitting too high. Lower it about 1.5 mm and the flames will not be so wide. This will reduce the contact with your pot supports and help with a cleaner burn.
Lots of opinions. I would not change anything until you have run enough fuel to ckean the pipes, then add fresh clean fuel and see. You said you just cleaned the stove. You do not say what you did. Ken in NC
Thanks for your thoughtful comments. I cleaned up the burner in citric acid and polished up the tank a bit, changed the wick and the graphite packing. The pricker was mangled so left that out when I replaced the spindle. The Coleman fuel was bought last summer. I've run it in my other stoves this winter without soot on the pot stands. Pictures are of the 3rd fueling of the 8r, which had just finished boiling three kettles of cold water at full throttle. I'm thinking I should try a new jet next, and will order one up. I've also got a BD silent cap on its way - any thoughts as to how that will affect things?
Based on what you just posted I surmise that your jet is too large. A cap helps just a tad with a worn jet but mostly its personal preference in making that choice. Don't forget about the spreader height once you get it running. Good luck let us have a pic once the jet is changed.
@Radler I agree as you say, the combustion dynamics with a pan can change things quite a bit. As Mark L says, it's always worth checking for a worn jet and work from there with fine tuning the plate, and happy with fuel quality. The supports just looked a little too sooty, especially so as it's naphtha.
Do you have a way to check the size of the jet? Different wires sizes? Thank you for the added information. Ken in NC
Wires of known sizes could be used to check, or swap in a known-good jet. Basecamp has them, or swap from a well running stove.
Was that a subtle hint @Marc I'm saving mine for a very rainy day......or at least till the other jobs around the house are finished.
Maybe not so subtle. (Don't feel bad about stoves, I've done the same thing with vehicles...........)
Hi, @Timothy Epp , Tim, It looks like you are priming with Coleman Fuel, is that right? If so, try using a good Marine Grade Alcohol, i.e. Methylated Spirits, for priming. It burns cleaner than priming with CF, and that just might be your problem. Worth a try...... Good luck, and God Bless! Every Good Wish, Doc
A bottle yellow HEET works well and is available everywhere for little $$. Make sure and get the yellow bottle, red is a whole different animal.
Raise the burner plate about 1 mm. That will entrain more air into the flame and oxidize the carbon more completely.
