Hi all I recently dug out an optimus 8r to fire up for fun. Has run previously on shellite although when I first got it the tank smelt of methylated spirits. However it would not start, I have ascertained it builds and holds pressure but will not allow fuel to the burner. Dunk test showed a bubble from the jet (Not blocked) approximately every 5 seconds which occurs for under a minute before stopping. The wick looks to have a green tinge also. If I open the valve while tank is under pressure no air or fuel escapes but opening the filler cap releases pressure. Could it be the generator is blocked somehow? The jet orifice is clear and the needle seems to be operating correctly. Any advice would be much appreciated
Hi, It may be a carboned-up burner but I would say this has all the hallmarks of a choked/burned-out wick in the feed tube. Left running until dry or incorrect preheating can cause the wick to dry/char/choke-up inside the feed tube (which doubles as a vapoiriser). HERE is a great tutorial from Ian Marson I would temper the advice by saying to unscrew the burner from the tank I have had best results by holding the burner hex flats in a bench vice and firmly twist the tank to unscrew it. Don't lever/twist by the end of the burner/control tap, you'll twist/shear the feed tube off. If it hasn't been off before, it may undo with a fair old "crack", protect your knuckles and the tank against the vice.... When you replace it, use a smear of high temperature lube for any future disassembling works. Oh and photos, we like photos Let's see what that wick looks like Alec.
Hi Alec @Rangie Thanks for the link all the info needed in one extremely tidy basket. The vice tip I will definitely take as it does not appear to have been opened before. And I was a little concerned about that step. Thanks again and watch this space for photos of the wick. Which really is a strange shade of green.. Any ideas why that would be? To long without fuel in tank maybe? Scott B
I've seen wickie lantern wicks get contaminated and turn green, maybe that's similar to what you describe. Can you take pic? If a previous owner had installed the wrong type of fuel, then sat for several years, maybe that caused some issues. Just spitballin' though.
Here’s what the wick in my Optimus 8 had degraded to. Technique I used to remove the burner from the tank. With no hexagon flats on the burner stem there’s no other option, but I prefer the method even when there is, with no risk of wrench (or vice jaws) ‘camming over’ the soft brass tips of the hexagon. New wick installed. Burner output restored. John
Thank all for your advice Coupla questions. @presscall Hi there What diameter is the hole in the timber? Drilled before cutting i'm guessing? @snwcmpr Hi there Do you mean try and run the stove without the pricker? If so what is this testing for? Thanks again guys
Scott If you drill the hole at the same diameter as the tube, then use a fine saw to cut the block, that should give you enough grip. Testing the stove without the pricker/rack lets you know that the fuel feed and shut off is operating properly and not being interfered with by an incorrectly set pricker rack. Cheers Tony @Scott B
@presscall @Tony Press @Rangie @snwcmpr @Fettler Hi all Thankyou again for your advice. Here is the 8r in action after an interesting yet satisfying wick replacement. First I stripped her down, The wick removal didn't go as planned... the wire pulled out without a substantial portion of the extremely tightly packed wick, which remained inside the tube so tightly that a long and thoughtful head scratching and staring at said tube followed. The wick was green and brittle I suspect that the stove has been run on methylated spirits in the past, the smell before I cleaned the tank was horrible. Anywho due to the lack of compressed air I proceeded to "carefully" run a 1/8 drill bit through the compacted wick material in the hope of it coming out, not so easy, I ended up winding a course thread timber screw into the remaining wick and pulling it out bit by crumbling bit....until out came a piece of material containing brass wire... I suspect a leftover from a previous attempt at renewing the wick, completely blocking the path of fuel due to multiple scorchings while attempting to fire burner, The flame is still showing alot of yellow but I am hoping after a few burns this will improve? Scott B
@snwcmpr The pricker only seems to go in 1 position. How does one adjust? The 8r doesn't shut off completely, When lit turning to the clean position and a little turn back towards open should be the closed position? However a small amount of fuel still makes it through the jet. Any advice on this? After a couple of boils of the kettle the flame did get to the happy blue clean flame, Regards Scott B
Try it without the pricker. How well does it start up? How well does it run? How well does it shut down? If all good, the problem is that the pricker was set incorrectly. So, next ... Learn to set the pricker correctly. If not all good, solve that problem.
https://classiccampstoves.com/threads/fitting-replacement-parts-on-regulated-burners.8843/ optimus 88 pieces
