The Cessna 120-140 Association Forum

Are there any STCs or field approvals to install a 150 fuel selector in the 120/140 to provide just the on/off selection vs. only one tank at a time?

8349 wrote: ↑Sat Jan 25, 2020 3:06 pm Are there any STCs or field approvals to install a 150 fuel selector in the 120/140 to provide just the on/off selection vs. only one tank at a time?

You cannot feed from both tanks simultaneously unless there is a tube connecting the air spaces of the two tanks, as there is in the later systems and the 150.

Hey Drew,

I've noticed your USA map signature in your posts showing some colored states. Are these states in which you have flown your 120/140? Man, that's a long leg of a cross country from Pennsylvania to Nevada! I suspect there's an interesting story hiding there. I flew my first C140 from McGrath, AK, to McAlester, OK, but had to make quite a few stops along the way!

To keep this in the subject of the fuel selector valve thread, the valve would get a good work out with the number of cycles on a trip from PA to NV!

Steve H

Hi Steve,

Just the various states I have flown in. Actually, the only place I have flown a 140 is in Australia. Looking to get one here in the next year to two though.

I think the map is pretty neat! I bet when you get your 140 you'll have a lot more colored states in a short time.

There aren't a lot of us that have only flown one in Australia!

Steve H

I would strongly recommend that you do not modify your fuel system in any way.

The Left-Right-Off valves are a much better fuel management option over "Both-Off" valves and there have been several accidents as a result of people modifying the fuel valves and fuel caps on C-120/140 planes.

KISS is a good approach. L-R-Off is a fuel system that is simple, reliable and allows you to know for sure where your fuel is at all times. With the L-R-Off-Both system, fuel will equalize between the tanks in either the Both or Off position. What happens if you are in the both position and one tank develops a leak? There are a lot of ways to manage fuel, i.e., when the minute is on the right side of the clock, select the right tank, etc.

Not saying you should convert a LEFT-RIGHT system, but L-R-BOTH is the best of both worlds. You can select BOTH for take-off which of course is the safest option, and then switch in cruise to LEFT or RIGHT for fuel management if desired.

The fuel selector in my '46 140 serial # 8015 is LEFT-RIGHT-BOTH OFF.
I've owned her for 27 years and all I've had to do to the fuel valve was
to polish the stem assembly and replace the o-ring.
I am Blessed.

Larry Surratt
1946 C-140
#89011
serial # 8015
R26

Not to get repetitive, but, you cannot (legally) install a valve that allows feeding from both tanks simultaneously unless the air spaces of those tanks are connected.

Also, the L-R-Both-Off valve actually connects the left and right tanks together when in the off position, which allows fuel transfer between the tanks.