Went to the airport this morning to take a friend up for a flight. On preflight, when I opened the left main fuel cap, fuel began overflowing the tank and their was an audible rushing sound. This wasn't a trickle...there was a large puddle on the ground.

After some trial and error summing and refilling various tanks and seeing where fuel was coming from, we suspect fuel is draining from the right aux to the left main even if neither of those tanks is selected.

Am I correct to assume this can only be possible due to a fault in the fuel selector? Either corrosion or debris?

Our mechanic was just touching each tanks sending unit trouble shooting a fuel gauge issue. Does that offer any hints or other potential problems?

If it's the valve, any suggestion on sources for a new valve and or rebuild service?

If it matters, ours is a fuel I jetted 260B

Thanks,
Tim Q

Tim,

Been there, done that, have the T-shirt for my Twin it was the fuel selector. O/H at Webco, happy ever since.

Happened even though we are zealous about sumping before first and after last flight of day.

Tim,

Check with Matt Kurke at Comanche Gear on the fuel selector.

Thought I'd follow up and close the loop on this one. We pulled the fuel selector valve and sent it to Matt at Comanche Gear in Florida. He serviced the unit and sent it back working good as new. Pretty sure it entails cleaning, Polishing the rotor, replacing the o-rings and adding some lubricant. Attached some photos of the unit taken apart in case folks are curious what it looks like inside.

We also had some issues with fuel gauge. Matt has a replacement kit for the circuit board and buttons that control the signal going to the fuel gauge. So we picked up one of those too. Super easy install and everything works great and was only a few hundred bucks all in. If you are doing work on the valve and have gauge issues, I highly recommend replacing the electronics too.

Hi ,

I am having a similar but differant problem on my 65 260B.

I "burn" about 2 gallons more out of my right aux yank than my left under exact same settings.

Yet my total fuel burn stays at 11.5 gph all the time?? So, I have to assume it is transferring to another tank somehow???

Also, the 11.5 gph seems quite low , even for fuel injection. Yet it runs at 1150 egt and 330 cht all the time. That is low.

I am new to the forum and just got my Comanche so I am hoping to dig up some answers.

Bob Bullock
352-459-1422