This might sound stupid, but have you tried having one tank empty, and seeing which way the switch allows the engine to run?
 
This might sound stupid, but have you tried having one tank empty, and seeing which way the switch allows the engine to run?

Therein lies the problem - there's some contamination (water) got into the carb and this has happened twice now. I also have two tanks full and nowhere to put it - so I need to deal with one tank at a time, hence the question!
 
Drain a gallon or two from the tank into a billy and strain it through a chamois leather. Water should stay behind.

Barring that decant into a glass jug and allow to rest - water will settle to the bottom and can be left behind and the fuel decanted off.

Reminds me of a rig i built for separating water and oil - container with a hose/spout leading up the side tapped into the bottom corner of the container. Water/crap easily pulled off leaving cleanish oil behind.

Daughter won a science fair with a cleaned-up version of that. :)
Alan
 
The military selector tap points to the tank in use. Turn towards the offside for the drivers tank, nearside for passenger tank.
I had a similar problem with persistent fuel contamination with my military 109. It repeatedly choked inline fuel filters. In the end I drained the drivers side tank, dropped it and cleaned it out. Its a quite simple job but definitely not safe enough to recommend.
 

Similar threads