silicon and fuel

[whisper]

When installing the fuel level sender unit in one of IFH's lower tanks recently I elected to use red RTV type silicon as a sealant on the gasket. BIG MISTAKE

When screwing in one of the mounting screws a small "sausage" of silicon fell into the tank. This then morphed into something many times the size and finally lodged itself in the fuel transfer pump.

A small piece also made its way into the main tank. Fortunately that has a finger filter at the outlet so the engine was never starved of fuel.

Lessons learnt
1) Never use a silicon based sealant anywhere near fuel....ever!
2) Use finger filters at all tank outlets (even ferry tanks)
3) Install a filter on the line between the ferry tank and main tank

Pics show the difference in size between the same blob of silicon before and after being immersed in fuel.

[Johan Nortje]

The same happened to me in 2006 when I use silicone to seal the sensor on the main tank. In my case the result was an engin out while still close to the airfield. I could glide back and land safely. After inspection the silicone block the fuel filter.