Fuel Line Leak Test

Got a question.


The idea that a fuel leak would show up when the tanks were first filled crossed my mind as I was installing the fuel lines. Ironically, about the time I had the fuel lines in place, Mitch informed me that the manual had been supplemented with a section on this very topic. The Cubcrafter’s approach involves pressurizing the system and using soapy water to check each fitting for tell-tale bubbles.

I pursued a bit less messy approach.


1. The forward and aft drain lines were plugged. The aft with a radiator bleed valve, which fit perfectly; the front with a piece of 3/8” hose and a bolt.

2. Four balloons were attached to the lines that attach to the fuel tanks. These are cheap Wal Mart party balloons which hold air for a day or so. Electrical tape assured an air tight connection.

3. The air compressor was hooked up to the line that connects the gasolator to the fuel switch.

Then the fun part. Pull the trigger on the air compressor and watch the balloons fill up! They were not all the same size, but they did all fill up. Then come back in 18 hours and they were still filled. So I should not have any leaks.

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I like this approach because:

1. You don’t have to worry about over compressing the lines. A balloon will burst long before the lines will.

2. No drippy soapy water to deal with.

3. No chance of missing a tiny leak with said soapy water

4. Adds a party atmosphere to a mundane work shop.

So here is the question: Is this a reliable way to confirm the integrity of the fuel system???