Annoying Optimus 99 glitch

Discussion in 'Fettling Forum' started by Onepot, Oct 31, 2004.

  1. Onepot

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    Took delivery of an Optimus 99 this weekend (from the States via Ebay). It has been messed around with and didn't really want to light (all the symptoms of no pressure).

    I stripped it down (I'm getting good at this) and examined the bits. First conclusion, the nipple (nipple? jet? whatever you call it) was loose so this was why it wouldn't light properly. The wick looked fine, albeit a little scorched. I didn't bother withdrawing the spindle becasue I reckoned that any problem in that department would have showed itself when I first lit the stove... and none did.

    After soaking the bits in vinegar and cleaning out the tank I slapped it back together and primed it.

    It briefly roared into life, but soon went into an ultra-slow version of the pulsing that had plagued my Svea123. Also the flame was very off-centre.

    I shut it off and examined it. The burner cap was seriously out of line so I swapped it over with one of my others. When the stove was re-lit it went much better, but was still a little flakey.

    I shut it off and added more juice to the tank then lit it again. I've learnt now that you should only alter one variable at a time. The stove was much better and I let it burn away whilst I turned my attention to the bent burner cap. I mounted it onto my 123 and applied a bit of effort to get it looking straight. After a couple of attempts it was spreading the flame pretty evenly so I swapped it back onto the 99.

    When I re-lit the 99 it roared into impressive action, but the cap is still off-centre :(

    It's cooling off as I type this and I'll go back and try to straighten it out again. However, is it worth it? Will I ever get it straight? Would it be better to buy a new cap?

    Cheers
    GC
     
  2. bark2much

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    Howdy,
    The usual cause for a slow death of the flame is loss of air pressure through hardened seals on the fuel cap. 3/4 inch outside diameter rubber seal from plumbing section solves it. The small, check valve seal within the fuel cap stem needs to be punched out from Nitril rubber. Other rubber kinds will erode from the exposure to the fuel.

    For the burner bell that is not centered will send the flames lopsided to one side of the burner. It is annoying. A trick is to bend the angle of the flame spreader so that the vapor stream strikes the flame spreader near the right angle. You can do this while the spreader is hot. Not a pretty solution, but it allows the burner to send the flames to the proper places.

    Another way is to bid on a real rag 123 or 8R that no one seems to want, or too ugly to own, so that you pay only pittance for it, and you can use the burner bell assembly for your better stove.

    I have done this a few times, and it really pays off most of the time. For the rest of the time it did not work out, they just fill the shelf space as potential parts for the better stoves... :)
     
  3. Onepot

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    Cheers for the reply.

    I have got the bell to the point where three sections show a good flame, but one is about half as high. In reality this is still good enough to boil a cuppa in no time, but my thoughts were as yours: rob a bell off a duff stove.

    Mind you, I could just pop over to the Base Camp site and price one up :)

    Oh, nearly forgot... anyone know what thread size for the little bolt that holds the 99's burner in place in the tin?

    Cheers
    GC
     
  4. Onepot

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    I took the advice and played with the burner bell when it was hot. It was much easier to move. The flame is now fairly even and looking very healthy indeed.

    I would post a picture but wifey is in Spain with the camera.

    Like my recently-purchased 8R, this stove seems to burn better with every lighting. Anyone care to suggest why this is?

    Cheers
    GC
     
  5. bark2much

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    I notice that the old stoves behave better and better, as I use them more often. It is the case, especially, with backpacking camp stoves by Optimus, i. e., 99, 123, 8R, 80, etc.

    Guess #1: old fuel and other gunk associated with years of disuse get to burn out with repeated use. The new components, delicate tweaking, and fresher fuel--all add up.

    Guess #2: I treat them with loving care; it is only fair for them to return the favor by showing up with better performances :!:

    Glad to hear about the burner bell working right.

    About the screw for 99: if you are living near Base Camp, why not give them a call? Or, you can take the stove to the hardware store and try them out. There has to be one that fits.
     
  6. DAVE GIBSON

    DAVE GIBSON Subscriber

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    GRAHAM..
    i like the 99 so much i bought 2 on ebay..a canoe buddy brought one on a trip a few
    years ago and i was impressed by it preformance..the best part was the lid that can
    be used as a real cooking pot.. the little cup on the 123 is ok for a pot of mush or cup of tea but the pot/lid on the 99 will cook a meal of rice and freeze dry meat. the older coleman peak stoves have a great cook kit/stove box but are twice the size and weight.
    and why buy 2 stoves??..well after reading all the fetteling messages in the forum
    i thought having a back-up for parts would be a good idea---
     
  7. Onepot

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    I have to admit that I too have found the Svea123's pan to be a little limiting, but ideal for a cup of tea :-)

    I will use the 99's lid as a pan when I get the bloody sellotape off the thing. The item was a bit too well packed when it arrived. I could go for the burn it off approach, but I suspect that it will mark the pan for ever.

    So far I've found my 123 to be the most impressive burner with 1.5" flames at times. However the little 99 is starting to overtake it (to the point where I have been wondering about the integrity of the tank cap release valve) :)

    I use the 123 pan as my boiling time tester and the 99 seems to be the winner. I suspect the 99's pan supports aren't man enough for a big pan or kettle so a 1 litre test may be out of the question.

    As for the burner screw, there's a large nonferrous metal stockist around the corner with rack upon rack of stainless bolts and screws... I'll wander over there with the stove.

    GC