Hey guys,

its been a while since i posted...since i have had nothing to complain about with my plane!! However now i do, and it seems its common in the type.

1973 C182P PPONK with a 82" hartzell 3 blade, problem has just surfaced recently, after a flight my plane will be streaming fuel out of the right fuel tank cap. It seems like the fuel is being moved over from the left tank to the right tank in flight, this has just started and i only noticed it about a month or so ago. I have tried to run off the right tank in flight, or run only off the left tank in flight this hasnt helped at all. I have the fuel vent right behind the strut on the left wing.

I have the monarch caps, and have heard i may need to replace some o-rings in the cap...i have no idea!!! im truly stumped! is my new bigger propwash making the vent pressurize the tank?!?!

PLEASE HELP ME!!!!!

the fuel venting out of the cap is starting to dull my beautiful factory original 1973 paint and its pissing me off!!!


Mike Howard

Try moving that fuel vent out from behind the strut. That is theoretically an anti icing thing. Don't fly in icing, and life will be better all around, no matter where your vents are.

My guess is the other vent is peeking out from behind that strut, or.....aerodynamics are goofy on these shapes.

Move both vents slightly out into the airstream. I suspect that'll help. A 185 I flew did this, and tweaking the vents did the trick. The are pretty easy to "adjust" with a little pressure.

MTV

What if you switched the caps around to see if anything changes? I don't see how this would do anything but who knows...

I've posted on monarch caps a few times. I know a few people that have had fuel siphon out of the caps in flight multiple times. I was on a flight with a buddy - he had them on his 180. We had siphoning going on, and landed with something like 2 gallons in the tank (had 15 gallons or so that we lost in the air) The cause was a compressed o ring on one of the sides. It will be deadly to someone one day if you ask me. I've now heard this story over a dozen times, and who knows how many more people that have had this and not reported it. Don't know if that's your issue or not. Scary.

Garth

Hey Mike,
Do not despair, this is not an uncommon problem. Cessna Pilots Association puts out an excellent 5 page Tech Note addressing this. It has lots of diagrams and explains the problems and fixes. It's Tech Note No. 003. If you can't find it on their web site I'll be glad to send it to you. Just send me your e-mail.
Their site is: http://www.cessna.org
Sam Allen

gear wrote:I've posted on monarch caps a few times. I know a few people that have had fuel siphon out of the caps in flight multiple times. I was on a flight with a buddy - he had them on his 180. We had siphoning going on, and landed with something like 2 gallons in the tank (had 15 gallons or so that we lost in the air) The cause was a compressed o ring on one of the sides. It will be deadly to someone one day if you ask me. I've now heard this story over a dozen times, and who knows how many more people that have had this and not reported it. Don't know if that's your issue or not. Scary.

Garth

Garth, I doubt the problem is the caps in this case. It's more likely the underwing vents.

I've flown several airplanes with the Monarch caps and never had a problem with them, except when I left one in my pocket after fueling at a remote site, then took off..... . We had them on a dozen or so Cessnas, and I've had them on my 170 for a lot of years, and never a problem. Maybe we were just lucky, or you're unlucky, but I'd never heard of the Monarch caps having these issues before. Different experiences are good to hear about, in any case.

MTV

Butch Hartwig at Monarch hands out the CPA's diagrams for where the vent is supposed to be. He button-holed me at OSH one year and after a half hour lecture (well, maybe only 5 minutes, but it seemed like half an hour ), I became a believer--where the vents are is critical, and not just for preventing icing. It's a good guess that yours have moved enough to pressurize the tanks, and that pushes the gas out of the caps.

Cary

As Cary said, the vent location seems critical. My vent line was located as close to where the vent diagram indicated as I could discern. I had the opposite problem as you though...the right side bladder was collapsing (getting pulled off the hangers, too) due to it having too much suction. I watched 10 gallons go bye-bye getting squirted forward out the vent against the strut in a half hour right after I leveled off for cruise. The problem began right after it came out of an annual, so I think there was a change to the upper strut fairing that may have made the difference.

I tried everything. Then removed the inspection cover by the vent, released the vent clamp, and moved it down a bit to be more or less completely in the air stream rather than partially obscured per the Cessna sketch.

Fixed the problem, and I have not had any blue stuff draining out the caps like you have. I had already replaced the filler cap gaskets with tighter fitting replacements too.

If you play with vertical vent placement a bit (the hose clamp inside the inspection cover) and seal the tank caps, your problem might go away.

Good luck.

Had the same exact problem. Put the vent back in the correct location (figured I must have bumped it with my head or something) and the problem went away. Good luck.

I can't figure out how all this gas gets by the caps of some. I just put fuel in mine a couple of hours ago and made a point of filling the area above the little flapper deal with the twist cap off. It holds fuel for quite awhile without running past the flapper and into the tank.

mtv wrote:

gear wrote:I've posted on monarch caps a few times. I know a few people that have had fuel siphon out of the caps in flight multiple times. I was on a flight with a buddy - he had them on his 180. We had siphoning going on, and landed with something like 2 gallons in the tank (had 15 gallons or so that we lost in the air) The cause was a compressed o ring on one of the sides. It will be deadly to someone one day if you ask me. I've now heard this story over a dozen times, and who knows how many more people that have had this and not reported it. Don't know if that's your issue or not. Scary.

Garth

Garth, I doubt the problem is the caps in this case. It's more likely the underwing vents.

I've flown several airplanes with the Monarch caps and never had a problem with them, except when I left one in my pocket after fueling at a remote site, then took off..... . We had them on a dozen or so Cessnas, and I've had them on my 170 for a lot of years, and never a problem. Maybe we were just lucky, or you're unlucky, but I'd never heard of the Monarch caps having these issues before. Different experiences are good to hear about, in any case.

MTV

Your probably right mike. I think I've vented enough about the monarch caps for awhile anyway, so I'm going to tuck my feelings about them in the drawer

If you ave fuel squirting out of the opposite vent in flight, then you have a bad or missing flapper check valve in the vent line. It is a fat cylinder between the vent line & the bladder (#16). It is a swinging flapper with a rubber seal on one side with a weak spring to hold it closed, but open to allow air into the tanks. It is supposed to keep fuel from being pushed out of the tanks through the vents.
This is in the 185, but it is similar in all Cessnas:

Maybe I should add that the flapper I'm talking about is in the Monarch cap deal . That little spring loaded flap that is about 1 and 1/2 inches down in the fill hole. It is basically a flat cork. I think all the screw on umbrella cap does is keep rain out for the most part.

Thanks for the help guys, sorry for my delay getting back to you all. My head bumped the vent and all is fixed!!

Mike

Oh yeah....the old "Adjust Head" thing...

MTV

What's that in the road, a head?

Cary