Clean Fuel

I recently made up a rig consisting of a 2' length of copper tubing, some 1/4" clear hose, and a priming bulb normally used on the hose between outboard motors and their gas tanks. I've seen this mentioned in other texts.

The fuel tank on Scamper was built with several threaded connectors on it's top, two are in use - one for the engine and one for the Espar heater (plus the returns ). There are two extras that have caps on them. I removed one of the caps and put the copper tubing in there and pumped out a half gallon or so. I kept moving the tubing around and it picked up an alarming amount of black fuel. I did this until the fuel consistently came out clean.