Hello from France My name is Yannick and I have discovered the beauty of these little brass stoves : Svea, Primus, well... you know what I mean... I’ve just found a Primus 71 (made in 1946). I would like to use it but there was no key. So I have ordered one (2,75mm) in brass and should receive it in a few days. Do you have any advice to make it works. I also have no pricker... The wick inside seems ok too. Thank you for your help and very happy to become a member of this group. Yannick
Hi @Yannick, Nice looking stove. Do you have the case for it? I see that your stove seems to have a feature to adjust the fuel to air mixture. Have a look at this Pr. 71 with similar control: 1939-primus-no-71.16107 Best Regards, Kerophile.
Thank you. I don’t have the case. I have to find a cookset for it. Indeed it seems there is a feature to adjust the fiel to air mixture. Is it an interesting feature ? Without pricker how to clean the pinhole ?? Yannick
A pricker is the only safe was as you do not want to enlarge the aperture and brass is quite soft. The correct jet aperture should be 0.23 mm diameter, so a stiff wire of about 0.2mm diameter is needed. Some people use a suitable wire from a guitar string. Another possibility is to used a carefully measured wire from a wire brush. Best Regards, Kerophile.
The original pricker Primus 4608 is not to be found everywhere today - http://www.fogas.se/rwdx/files//71E-71K-71LS.gif The pictured partially closed air shunt was used for the common gasoline/alcohol mix in late 1940's - it should be fully open for fuel without alcohol. It is easy to service the jet when burner bell is taken off and that is easiest to loosen when it is hot.
Thanks Lennart you mean we can use this stove (with this particular bell) with a mix of alcool and white gaz ??! If so do you know the percentage of each ? Yannick
I remember this post with an instruction sheet for the Primus 71. https://classiccampstoves.com/threads/primus-no-71-1945-with-air-fuel-mixture-adjuster.292/ In the instruction sheet is a reference to "Discol fuel". When using this fuel the "airholes" should be reduced. Discol (sold as Cleveland Discol) was a mixture of gasoline and ethanol (alcohol). I was not able to find a reliable source for the percentage of alcohol in the mixture (25 % ethanol is mentioned....). So yes, the Primus 71 should be able to run on a mix of gasoline and alcohol, but the composition might require some experimentation.
However, (after some further reading) you should be using 100% ethanol as an addition and avoid the introduction of water. Addition of water to an ethanol-gasoline (white spirit) mixture can induce phase separation, comparable with trying to mix oil and water.
Alcohol is best used as a priming fuel and the stove is best run on pure Naptha [Coleman Fuel, White Gas, Aspen (UK)]. Automotive Gasoline, Petrol, Essence has modern additives good for 4-cycle engines, very bad for human health. Avoid Gasoline.
Hi, this reference again mentions Discol as a mixture of gasoline with 25% ethyl alcohol: ALCOHOL FUEL FOR HIGH COMPRESSION ENGINES - Motor Sport Magazine Best Regards, Kerophile.
I think you tagged the wrong Yannick there Kerophile. Still, rather serendipitous: I do not get to meet many other Yannicks. Bonjour Yannick, enchanté! Good luck with your stove!
