I am fettling a relatively goodlooking Shmel 2. After replacing the seals and pips she burns very nice, but she refuses to completely close. After turning the valve completely clockwise, a small candle flame persists. When I exert additional force on the valve the flame disappears, but as soon as I let go there is fuel escaping. I have removed the spindle and cleaned it with a soft cloth. Inside the burner some dust or small particles could be seen on the seat, so that was also cleaned. After reassembly the problem had diminished somewhat, but was not completely resolved. Suggestions on how to proceed are very welcome!
@Huub I suggest you tighten the spindle packing nut to prevent the spindle ‘backing off’ as you describe. The Shmel is largely ‘on’ or ‘off’ with a simmer setting tricky to achieve (though it can be improved, as HERE) and has a control key that offers a good measure of leverage. In short, there’s scope to tighten the spindle packing to make the spindle quite stiff to turn.
@presscall Hi John, thx for your fast reply. I have followed up on your suggestion, but without the desired result. I have tightened the spindle nut until the spanner gave signals of serious resistance. Subjectively it has worsened the situation, the candleflame is now a bit more difficult to suppress. I suspect that the surfaces of spindle and seat do not match (enough). The question is how to improve this. Removing material from the spindle is the only option, but also rather irreversible so I'm a bit hesitant to use the hack you described earlier.
Hi @Huub . When I look at the photo of your, removed valve, I can see in the photo that the flat part of the valve that allows guidance, comes to the edge of the cone that closes the fuel supply. Perhaps (you can't see it in the photo), it is somehow shearing the cone a bit causing the leak? In my Shmel you can see that the flat (ground) surface, does not reach the cone. It looks similar in John's @presscall example. Just such a guess that it may be a manufacturing defect. Greetings Stanisław.
was a few versions Shmel 2 with unusual burner no matter what You have both valve surfaces are important for proper works on spindle and in the burner "body"
Thanks for bringing awareness @gieorgijewski . I have two Shmel 2 with one type of valve, hence my assumption (wrong). In this situation , it occurred to me that the valve Huub writes about may have been swapped from another burner. Unless the stove is new? Then I have no idea anymore ...
@presscall @Knee @gieorgijewski Thanks for your time and interest! The stove looked new and unfired, so a parts mix-up is unlikely. The fount did not smell like gasoline and the burner also looked new. The only thing I noticed was that the pricker was at it's highest position with the valve turned completely clockwise.... After re-inserting the spindle this was corrected and the normal situation restored (pricker in highest position in the middle of the valve movement). In the meantime I have honed (correct word?) the closing section (tapered part) of the pricker assembly with very fine sandpaper, but without the desired result. I did not realise that closing is performed by contact between the tapered spindle and the sharp edge of the riser tube; I presumed that the end of the riser tube was a mirror image of the tapered part of the pricker assembly (like a funnel). Since the tapered part of the spindle looks okay to me, there is possibly a small defect in the sharp edge of the riser tube?? I'll try to make a picture of this part. To be continued and I'll keep you up to speed.
That’s right, as I described in THIS topic: It might work, or might deform and not seal. It would reduce the arc of rotation of the control spindle. Heat conducted from the burner would reduce its service life I expect.
Your Shmel is fabricated in late 80 or even in early 90. It can be simple defective from the factory, because it was end of USSR and nobody cares about quolity. You can try to fix this. At first you need to polish that conical element. After that turn on the stove, give it to work for 10-15 minutes at full blast, so burner became very hot. Now turn off-on (few times) the stove using a lot of muscule power. The idea is to make good fit behind steel conical element and hot soft brass burner. It can help you. P.S. Sorry for my poor english
@Kroton You don't need to make excuses for your English, it is good to read and understand! I have already tried your suggestion this afternoon, thinking that the conical element is hard steel and the burner seat softer brass, so that the steel will form the brass. I will do it again tomorrow after letting it burn for 15 minutes. Next steps: 1. polish tapered part of the pricker block (again) 2. clean / polish inside of burner (again) 3. follow Kroton's suggestion after longer burntime and if all else fails - change the shape of the tapered section, method presscall.
