11-19-2010 Ask Mike! Archive Page
Cessna Fuel Caps 

Hi,

I have a 1975 Cessna 150M with mismatched fuel caps.  The plane looks great, but these caps look ratty (faded and chalky).  Also, I experience an uneven fuel flow in operation, with the right tank draining faster than the left.  I have been trying to find new replacement caps with no luck.  Any advice would be appreciated.

Tom,
West Dundee, IL

Hi Tom;

In 1977, Cessna introduced the vented caps; the 150's and 172's required only one, on the right side; other models used a vented cap per tank.  They were a plastic cap that faded and generally looked poor after years in the weather.  The new style is metal, and looks better longer.

If you are draining the right side faster; I would suggest 2 things:  The underwing vent on the left side is probably plugged; we have found that on a number of Cessna.  The underwing vent is the primary (and before the service bulletin & airworthiness directive came along, only) vent.  With the underwing vent plugged, probably by bug debris; that makes the vented cap that is on the right wing the sole vent source.  (Note that the tanks are inter-connected at the top for venting purposes between tanks, but may not be quite sufficient to counteract the plugged underwing vent.)  After cleaning that vent, second suggestion is to replace the left cap also with a vented type.

The part number cap you are looking for is C156003-0101, Cessna is showing stock at $45.90 each.

Mike

Thank you, Mike.  This is great information and tells me everything I needed to know.

Happy Thanksgiving!
Tom