Horizontal is fuel on!

Every Spring I drag my Huskavarna lawnmover out to start for the first time and I can't remember whether the petcock is in the OFF positon or ON position. I look at the petcock and I can't tell. So after cranking on it in both postions and finally got it started and Now  I know.
The odd thing is that the the petcock itself is miss-marked. If I twist it down to the horizontal position the fuel icon with a bar across it shows  shows on top, and also a small red mark lines up om the top of the valve, so it stands to reason that it should be off, but in this position it runs and and runs. If I turn the knob to the  verticle position it will run out of gas in a couple of minutes. I have never seen a petcock so ambiguous. 

All I have to remember is if it looks off, it is on, and vice versa!