jigeye

I have a nitro fuel tank with three holes. I understand everything, however, I really don't need the fuel filler hole as my engine is not in the cowl and I just "refuel" through the vent tank tube (connected to the muffler). What technique do I use to "plug" the hole I don't need?

A. J. Clark

There's a couple of ways to do it. But first you won't be able to use the vent line to fill unless you have a second vent line to let out the pressure in the tank that is generated from filling it. If you can't fill through the line that goes to the carburetor you will need the third line.

if you want to plug the third hole you can take a piece of brass tubing crimp one end closed then solder it it shut. Or put fuel tubing on the end of the brass tubing and plug it with a fuel dot .

Hydro Junkie

An alternate way would be to take a piece of appropriately sized brass rod and insert it into the hole. Personally, I would just get a new tank plug kit and replace the soft parts inside the tank. Since the plug has at least one hole molded shut, you don't have to worry about it leaking around a brass plug since there wouldn't be an opening there to begin with. I have to agree, however, that filling through the vent won't work without a third open port since the air inside the tank will not be able to get out except through the carb line which will mean the plane would need to be standing on it's nose to get anywhere over roughly half a tank

Lee Taylor

In the old days we used 4 holes. One for the engine, one for the tank, one for the fill, and one for the drain/vent. I suppose a piece of round stock (metal) would work as a plug. Measure your tubing with a caliper and find a piece of solid metal the same diameter. Just a thought. Whatever works

jester_s1

Just get a new tank stopper. It's only a couple of dollars. If yours is more than 2 years old it probably needs replacing anyway.

jetmech05

How do you fill through the vent line? Once fuel covers the clunk there’s no way for air to escape.
fill through the line to the carb yes not the vent.
if you are filling through the vent your tank isn’t plumbed right.
you did plug the 3rd hole in the stopper didn’t you