The Cessna 120-140 Association Forum

I just had a annual done and my mechanic was concerned about my gas caps. I have owned my aircraft for a short time and my aircraft mechanic was concerned that the gas caps have two holes drilled in top of them which allows water to get into the tanks when it rains. I need to replace these caps, they need to be vented since there are no fuel vents outside the caps. Any suggestions?

tdinman

Those are the Original gas caps installed by Cessna.

Please go the Neal Wrights articles toward the bottom of the Forum webpage and look at the article concerning the 140A gas caps.

It also give good information on the 120/140 gas caps.

Rick

The caps you have are correct. Get two cat food cans and bend them a little so they fit tightly over the caps. Put them on to keep the rain out.

As stated by others, the caps are correct. The tanks must vent in order to feed properly. Check the holes to make sure they are not blocked. Cat food cans are great if the aircraft is not hangared. If you happen to forget to remove them, they will most likely be blown off before you get airborne.

My Dad left our airplane outside for years before I purchased it from him. It sat outside, year in and year out for almost 30 years. We seldom had water issues. The reason is that water drops will cover the holes and then following water will shed rather then enter the hole. As I sit here typing this, there is a term for how and why water does this and it escapes me. I'm sure someone else will remember it.

The real fix though is as mentioned, a small tuna can and squeeze it like a football a little bit and they stay on through most monsoons.

Surface tension - acts like a membrane and successive drops roll off.

I've always used the cat food cans. The aluminum one are very light and you can throw them in the baggage compartment. That said, I've heard others have had good luck with the rubber end off a plumber's friend, too.

4004 wrote: ↑Sun Oct 27, 2019 2:54 pm Surface tension - acts like a membrane and successive drops roll off.

Thanks, ..........tried to remember all day yesterday.........