Small Engines (Lawn Mowers, etc.): outboard motor, line tank, varsol

Question
Hi. I just bought a 1957 Johnson 5 1/2 horse outboard at a estate sale. The motor looks good, but the tank is a mess. Their was 1 - 2 inches of varnish in the bottom. This is the older double line tank (one air coming in and one gas going out). I cleaned the tank with gumout, but I still have a little varnish on the bottom and sides. My question is how do I clean the rest out? Also, the top has a long tube with a filter to pick the gas up from the bottom. Can I just connect a opper tube with a regular canister fuel filter to filter the gas before it goes to the motor? Any suggestions would be appreciated.

Answer
If swishing a bottle of carb cleaner around in the tank doesn't dissolve the varnish, put a handful of large stones (1" diameter) in the tank and some varsol mixed 50/50 with water.  Roll the tank around (not too violently) to allow the stones to act as a media to remove the varnish.  Then shake all of the stones and the varsol mix out.  Yes, you can put an inline filter anyhwere ahead of the engine in the fuel line.  Hope this helps.