Svea 123 or 123R?

optimus 123I saw a 123123R with a candle flame on the filler cap. I had been called over to fure out why it had a weak flame. I got the cap off and the fuel was boiling. TheJust showing how you can tell the difference between an Optimus SVEA 123 and a 123R. They are both great stoves and I'll post a review in the future. But in