This stove didn't come with a manual. I suspect this is around 1955 or so. The filler has a wingnut on top and pressure relief needle valve on the side. At first, the pump gasket was dried out. It now seems to pressurize the tank and I got a flame. Can someone tell me what to expect as to how long a pressure pumping will last and hot/large this flame should be. If there is a maintenance routine, that would help. Anything to avoid? Thanks, Dave
Welcome aboard the Ship of Pyros(Tm), Dave. You've lucked into probably the easiest stove to cut your teeth on. Usefully large, too It sounds like you have already had some success with, just a little tweeking and you'll be out looking for more stoves. No, really, this is exactly how it starts. It's called Stove Pox and it's easier to just not fight it..... The pressure cup is easily resussitated if it's not too raggedy, just soak in olive oil for a few hours, that will cheer it right up. If it needs replacing, the best pressure cups on the planet are available through this site via our Turkish connection, Sefaudi or just click on the The Fettle Box link on the right of this page. The only thing to watch for right now is 'Under Burn', as the name implies, the fuel vapour catching fire below the burner cap rather than above. Easily spotted, running normally the cap should have a bright blue halo ring of flame and a 'flat tire' type hiss. Underburn is a louder and more harsh sound and the burner cap will glow cherry red. Half the time the problem is the user lighting it from underneath instead of on top. Have fun with it, it's an easy and useful kerosene stove that could easily go another 50 years. Photos, man, we love photos!
Welcome to CCS, Dave, There are three "soft" parts to this stove, that dry out over time, and occasionally need replacing: 1. The tank cap gasket. If it is not soft, replace it (with a Viton gasket, available from the fettle-box here). 2. The pump leather cup. Soak it in oil from time to time to revive. 3. The rubber "pip" in the NRV (non-return valve) down the bottom of the pump. If it dries out, pressure will leak back from the tank into the pump, pushing the pump shaft out. If this happens, look up the instructions on this site for NRV repair. In addition, make sure you have a "pricker" to clean out the jet from time to time, or when it gets clogged. Make sure you only use clean kerosene in this stove. Never try Coleman fuel or gasoline. As to pumping, add a few strokes as the flame gets weaker - you will get the feel for it after a few burns. Enjoy your first Primus! Others will follow. Yonadav PS Please upload some photos, including a flame shot.
The pressure cup or pump cup is a leather cup down in the pump bore, it should be rough side out with the cup end facing down in the bore. When it dries out it contracts and doesn't make a good seal. The cap over the end of the pump should just unscrew, the NRV Yonadav mentioned is in the bottom of the pump bore. Welcome to the forum!
Thanks. Seems like the NRV works since the piston doesn't run out. I'll look at the filler cap seal and oil it. The utube was helpful to gauge the flame. But I think I'm doing more than a few pumps to get the same flame size. I'll give it another try in the field. Using this to heat up some chili for my daughter's riding team. Getting a lot of loose ends together. I'll shine it up and sent some photos later. Maybe I can find the date ID at some point.
Dave, The pump cup is made of leather, which after drying becomes soft again if soaked in oil. The leather cup works differently than the piston rings (although the purpose is the same) - the air pressure on the inside of the cup pushes its walls out, ensuring a tight seal against the pump tube. BTW, you have similar leather cups in vintage bicycle pumps. The tank cap seal is made of Viton rubber. When dried the only possible repair is to throw it away and install a fresh one. Oil will not help you here. A dried seal is the common reason why you have to pump a lot - air escapes through the bad seal. Yonadav
A few more words about the pump cup: (too late to add this as an edit to the previous post) The cup works as both a piston and a one-way valve. On the IN stroke, the air pressure tightens the cup against the tube, making a tight seal. On the OUT stroke, the air pushes the cup walls inwards, allowing outside air into the pump tube.
Once the stove is pumped to the desired flame level it should sustain itself at that level. If the flame reduces and additional pumping is necessary then you have a slow leak at the fill cap washer or NRV as discussed above. Ray
From all the great comments, I might have a slow leak from the filler cap. The NRV seems to hold. Is there a quick fix so I can use this tomorrow. I'll do more later. I have some thin cork sheets. Possible?
Automotive O rings. Lots of us use them at some time, some never use anything else (cost, availability etc) Ordinary rubber, inner tube etc is no good for other than (actual real) emergencies and then only for single use. That said, kero isn't half the solvent petrol is, but why tempt fate? A grab bag of O rings will be a few bucks at your local auto spares place.
Cork is prolly ok. They made NRV pips out of cork. Long term look for a Viton gasket from the Fettle Box at right.
Thanks to all. I carefully removed the stiff fill gasket and turned it over with a thin cork backing. Only two pumps got a very large and steady flame. Some yellow on the fringes but I think it will heat up a batch of chili for my kid's riding team. Conn College at Lee's on Litchfield Rd. in Litchfield Ct. Any CCS folks are welcome to stop by for some eats and to offer more advice.
Any hints on how to best shine the tank and maybe find the date stamp? I think it hasn't been used much.
Brasso (if you can get it), a rag and some late night TV has worked for me in the past There should be 2 letters stamped into the lowest point of the tank underneath, possibly covered with grime and gunge right now. once you have found those it's a simple matter of using the Primus dating chart here on the site and you are laughing. I'm gonna pick........1936!
I am with geeves on this. Brasso is good for shining clean brass. Autosol is slightly more abrasive and is the polish I use on all my stoves - cleans and shines all metals and leaves a mirror-like finish. These days, being rather lazy, I use the Autosol on a polishing pad in a Dremel. When I was a young 'rocker' (in the 1960s, the name given to leather-clad motorbike riders), I used Autosol to shine the engine block.
I have used Brasso for years but went off it a bit when they modernised the can with a plastic cap. I find Belgom Alu is very good.
