A few weeks ago I picked up a Sigg Tourist and Svea 123 from a local used outdoor gear dealer. At the same time I spotted an old Optimus 99 in excellent condition. I never had one of the flat box Optimus stoves in the past and actually never really had much interest in them…They always seemed big and cumbersome and just odd. But that shiny aluminum box just kept haunting me… So last week I read a few threads on this old stove. And that was a costly bit of reading. I decided it was not even possible to put this post in the Fettling forum as the only thing this fine example needed was a clean of the top pot and a fuel rinse. This stove could not have been used much more than a handful of times. It came with the pump but the little pump seal is “frozen” to the internal spring mechanism (pumping does not open the seal to add pressure to the stove tank) so that needs to be repaired…otherwise it is as good as the day it rolled off the line. Top pot cleaned, fueled and ready to burn. Nice strong flame even with the “R” type valve it is easy to get a full roar and a decent simmer setting. And boiling up in my old Sigg…rather than sullying my polished top pot. This stove will go into my truck as a perfect self-contained little tool. The whole configuration of this one will probably never capture my heart like the Svea, but it is an awfully nice stove I must admit….
Beautiful stove, burning as well as the day it was made. There is no spring in the pump, just an o ring, a vice and a spanner will get apart, and all will be revealed.
No the pump is fine. It needed its o-rings cleaned but that is all. The stove cap is where the issue is. The seal in the cap is frozen to the stem so it does not allow air to push into the tank. Once I pull the cap apart on the inside I should be able to replace the seal or peal it off of the bits inside so it works.
This is what I mean Knight84 posted this in one of his threads.... That little seal is solidly fused to the little stem in the cap so no amount of pressure from the pump will open it and allow the air into the tank. From this thread.... https://classiccampstoves.com/threads/15521
After a bit more reading, I believe I can clarify... The NRV seal is fused in place and needs replacement to make the pump functional. Once the Fettle Box opens I will order some little seals.
Hi Schwert - have you tried pouring a little liquid wrench or brake cleaner down the SRV tube, or put the entire pump cap in WD 40 (or similar lubricant) to see if that helps? I've had plenty of SRV PIP's 'fused' to the metal air intake, more like dried or heated stuck. They've always been able to free up with some oil and time (24 hours sitting). Straighten out a paper clip or use a thin nail and push it down the metal tube (where the pump would fit over) to help dislodge it by pressing down. You'll have to replace the PIP anyway, if she's stuck fast it's most likely hard as fired clay and won't hold pressure. The 99's are good, compact little stoves.
I understand what you are saying. However also compare the end of your pump to the pump in your last post. The second one has an attachment with an oring that seals the pump to the cap. But in the first pics that part does not appear to be there. I may be wrong, I just have not seen a Optimus pump with a skinny end like that before
I will try the oil soak and paperclip push idea. I did soak the cap in white gas but that did not do the trick. Pump has two o-rings...one to fit the cap, one to seal the piston. I see what you mean about the more robust end on that other pump photo...but mine looks to be fully functional...maybe an early model.
Ah, Canadian Brew... A little WD and paper clip probing knocked the NRV seal loose. And as you predicted, it now leaks with an audible hiss.
Apparently I have a Optimus Mini Pump with a different shape than is considered “normal”. My pump has a narrow front piece where the o-ring is housed rather than the more robust blunt end that seems to be the standard configuration. The front piece of my pump is ‘delicate’ and appears to be machined aluminum with no wrench flats….whereas the more usual pump has a blunt ‘cast’ aluminum piece with wrench flats. I am guessing that my version is an earlier one, but have no idea if that is true. I have read through many of the threads here with pumps in them and have not yet seen one to match mine. A good photo of the blunt-ended pump can be seen in this thread… https://classiccampstoves.com/threads/11625 So here is what I have. The whole thing from the front: With the front piece unscrewed to reveal the piston and the o-ring housing.
Text on the worn label... Optimus Mini Pump Caution For Optimus Svea Stove Only Pre-heat Stove Normally Over Pressure May Cause Surging Flame pat applied for AB Optimus Inc Santa Fe Springs CA 90670
Looks like a good design. May be slightly easier to fit inside stove cases when you pack things away too. Some stoves are a tight fit with all the bits, 199 for example.
Greetings, Schwert, Nice find on the 99, and a lovely one it is, too! As to the pump, it is different than any I've had, or seen, and so maybe somewhat rare. Don't know for sure, though. I always dismantle my pumps, when getting them, and usually replace the O-ring, then give it a good rubbing with graphite powder. I used grease in the beginning, but when it gets cold, that grease seizes up, and makes the pump balky and slow. The graphite powder works perfectly, no matter the temperature. Thanks for sharing your fine little 99 here, and have fun with it! Take care, and God Bless! Every Good Wish, Doc
No need to pump if you pre-heat anyway. I only use the pump, on one SVEA 123 with a pump cap, to give a little bit of pressure to squirt fuel into the spirit cup. I don't use it to raise the pressure for more heat. Once it gets warm it has enough pressure. My 99 actually doesn't have a pump or pump cap. Ken in NC
