I was asked a few days ago to try to diagnose this familiar problem with yet another Optimus 200 and after understanding that Drew had got everything correct and was still getting a black mantle I had a thought and suggested he try to run the lamp without the pricker rod in place to see if it improved which might prove the Preston loop is blocked. Tonight he reported to me that after some trouble getting it to run the lamp eventually settled and after a while burnt off the carbon from the mantle and gave a good light again. So I conclude that in this case BMD was caused by a gradual choking of the Preston loop with carbon. This had the dual effect of reducing gas flow and also reducing the heat transfer into the fuel. Problem now is how to clear the tube. Heat and quench might work but there is always the danger of running the brazed joints. Perhaps the way is to cut the middle of the tube and bend slightly to allow a drill/brush out of the tube and then bend back and silver solder the join. Drastic perhaps but if that is the only way then there is nothing to lose by trying. Thoughts anyone?? ::Neil::
Remove the jet and soak the vapouriser for a day or 2 in vinegar or carbon cleaner and then use an air hose to blow out the muck, that procedure may need to be repeated, but it should work. Or one of those ultra sonic cleaners might do the job, Jeff.
You can clean an optimus vaporiser out decently with a thin steel wire and a power drill. The loop on most Optimus vaporisers attach pretty close to the jet thread, and is also attached in a pretty steep angle to the vertical tube. You can insert the wire there and once you start the drill (low speed), you generally can make it wander deeper and deeper into the loop. Then just run it back and forth with the drill running, tap the vaporiser, and continue. A good portion of flushing with acetone by pressing a plastic bottle with a spout in the upper loop attachment now and then shall also be done.
That's generally the same thing. A steel wire. The wires I use often comes from bowden cables. The end shall be split slightly and the strands can be bent backwards to form sort of a brush. I'm sure everyone has done this (but perhaps on other applications), and know how to do.
Is it still possible to obtain new vapourisers and J tubes and the fittings for the Optimus 200 lanterns? Jeff.
If it is for the later 200P then it should be possible to find vapourisers. If it is the earlier type then the only way is to find a lantern to scrap. The correct J tubes are like hens teeth. I'm missing a couple myself. Unfortunately there doesn't seem to be any Chinese lamps in the 200cp size that can be used for parts.
There are "carbon dissolvers" made for the automotive industry that are introduced into the carburetor or fuel injection system. After they sit the engine is started and an "Italian Tuneup" is done. The cloud of black smoke that comes out the tail pipe will block out the Sun. Perhaps some of this could be squirted into the ring and allowed to set. Another carbon dissolver I have used to clean my turkey fryer pot bottoms is Kleen Strip Aircraft Remover. It comes in an aerosol can as well as gallons. EVIL stuff it is. Wear a respirator. If you get a lung full it'll take your breath away. Lots of "nasties" in it like MEK, methylene chloride, and toluene. But it melts burned on carbon like butter.
Carbon dissolvers of different kinds will of course do some good. But in the end I have found that it's practically always needed with some mechanical treatment too to get a really clean vapouriser. Those deposits can be ridiculously hard and stay unaffected by the toughest dissolver alone. The rotating wire I described above works fine, but it's a bit fiddly, and take some time. Another simpler way that often work well in combination with e.g. acetone, is to just simply push the wire all the way through the loop and let it come out in the other end of the vapouriser. Then I tie one knot on it, and let that knot work inside the loop by attaching the wire between two fixed points and then just simply move the entire vapouriser back and forth. A squirt of acetone (or other suitable chemical product) from a squeeze bottle now and then helps. (A small screw tucked down in the narrower part of the vapouriser will force the fluid to take its way through the loop instead of just the straight and easiest way.) If the knot is replaced by some sort of real brush instead, I guess the work would be much more efficient. Perhaps it even would be enough to tuck some short pieces of a strand perpendicular in the twist of the wire to create a bit of more "scratchy" tool than the knot. Like a boresnake, if you're familiar with that (it's for cleaning gun bores). Another surprisingly effective and easy thing is to use steam! A lot of steam, and real working steam under high pressure. I tried that some years ago. If you drop a screw (an M3 is good for a 200 vapo) with the threaded part first into the attaching part of an upside-down held vapouriser it will steer into the constriction, but the screws head will stay above it. By this simple action, the easiest way is blocked, and the steam must go through the loop. That time I just placed a steam hose over the bottom part of the vapouriser and secured it with a hose clamp. Then I opened the 10 bar steam and let it do its job for a good while. Clean as a whistle! I think... it's hard to actually see inside the loop itself... This is of course not a thing to do at home, but I tried it at the plant where I work. We have two large boilers for among others heating the entire process. I got the idea since we also use the steam to clean the boilers themselves at the plant at certain intervals. High pressure steam is good on stubborn carbon deposits. Cleaning a lamp vapouriser is just the same. Only in a micro scale...
Yes, I don't think carbon itself can actually be dissolved. What you can dissolve are the other substances which are holding the carbon particles together and in so doing, loosen the deposit. Baked-on carbon with no other substances requires mechanical intervention of some sort to remove it. The BOFs here (including me!) will remember, probably with no fondness at all, having to decoke engines by removing the cylinder head and scraping off the carbon with blunt screwdrivers and the like...
Yep. I have to do that with the hot bulb engine I got in my boat. Not so often, but I take the cylinder head off and lift the entire piston out every third year, or so, just to check and remove some deposits especially between the piston rings. What's a BOF, by the way? An advanced guess would be "Bloody old fart", or atleast something with the word "Old" considering the context here.
Hi, I'm the source of the question. With some braided steel cable at 3/32, a little to big so I separated the bundles. Finally chucked it in a drill after trying by hand awhile. Had better results but still some sooting. Queched the generator at the site the braid had stopped at first and tried again. Still some sooting. Increased the gap between the J-tube and the top of the generator. I switched to a 21 mantle and tried again. Fettling success. It takes a little more pumping than in the past but it works again. Thanks for all the ideas on cleaning helix type generators. Drew
