fuel smell

hydroguy2 · Post by **hydroguy2** » Wed Dec 15, 2010 2:20 pm

Kinda makes you nervous when you smell fuel with under 5hrs on a new engine/airframe.

I topped of the tanks today to do fuel burn calibrations. I launched from RY16(3890msl), straight out and climbing ~2000fpm 115mph, shallowed the climb to about 1000fpm 145mph. Leveled off at 7500, and as speed increased to 175 it was getting pretty rough. I am still trying to breakin the engine, but no way I'm going to be able to run 24sq. The mostly cloudy skies opened up to the south, so pointed her to the blue.
As I climbed thru 8500' things smoothed out real nice, at 9000' climbing 1000fpm....I smelled fuel, Fairly strong considering I have lots of air coming under my canopy edges.

I'm 15miles south of the airport at 9300' 22.9" 2400rpm I was indicating 175 and 400fpm climb. Quick call to my buddy telling him I'm return to the field. I make a 180, switch tanks... everything good, smell is gone. But I'm nervous. I lean the engine to 12gph and reduce power to 20". I touchdown a little hot and balloon up, a tiny bit of rpm and she settles on nicely.
once on the ramp I shutdown and inspection showed nothing. Pulled the upper cowl and nothing indicated.

My hope is full tanks, bumpy ride and/or climb sloshed some fuel out a vent.

Any ideas or help?

cjensen · Post by **cjensen** » Wed Dec 15, 2010 2:38 pm

It would surprise me if you had a leak in front of the firewall, and could smell it. You wouldn't smell it from the vents either while in flight.

It went away when you switched tanks though, right? Check all fittings from the valve to the tank that you switched from to start. I really don't want to think about where my fuel smell was coming from...

hydroguy2 · Post by **hydroguy2** » Wed Dec 15, 2010 4:10 pm

Went back to check fuel levels. Right tank was down 2" from full. I only ran this for 10 minutes. No loose fittings, so wonder if I siphoned some out.

hydroguy2 · Post by **hydroguy2** » Wed Dec 15, 2010 6:39 pm

After I had a late lunch and thought about things I went back to the airport, Unable to find anything, I figured I may as well take her up again to do a sniff test. Run up good, climbing again at roughly 2000fpm and shortly later got a faint whiff of fuel.....level off, nothing.... switch tanks, nothing. zoomed around for 1/2hr, with a couple shallower climbs and nothing noteworthy....except the truly fantastic performance I experienced!

cjensen · Post by **cjensen** » Wed Dec 15, 2010 8:10 pm

Keep us posted on this one Brian...

hydroguy2 · Post by **hydroguy2** » Wed Dec 15, 2010 9:01 pm

yep I will. This weekend, I'll be pulling all the interior covers around the fuel system for a look-see. Don in Idaho said he a weeping fuel valve that would give a smell of fuel and took a long time to find.

Wicked Stick · Post by **Wicked Stick** » Wed Dec 15, 2010 9:57 pm

My guess is the vent lines may be leaking inside the cabin ?
Check for loose fittings as they come into the cabin and where they exit.
It usually shows up when you have filled the tanks full and it expands up into the breather line. Look closely for any blue stains

.

One morning as I arrived at the hangar and slid open my canopy before a flight, I noticed a fuel smell. I was about 9 hours into my phase one at the time. A closer inspection revealed a small amount of blue stain on one of the lines attached to the fuel selector. I tightened them a bit more (maybe 1/2 a flat or so) and wiped the line clean.

The smell has not returned and no further weeping in that area.
I guess I was just a little on the cautious side when tightening them as I didn't want to crack one by overtightening it.

Let us know if you find anything.

hydroguy2 · Post by **hydroguy2** » Wed Dec 15, 2010 10:13 pm

With only 5 hrs on everything I'll be cautious. Probably just a fitting that loosened up.

Curious why I only smelled it during a climb.

Bob Barrett · Post by **Bob Barrett** » Thu Dec 16, 2010 6:46 pm

Brian, I don't have the right fuel tank cover adjust just right and a couple of times on climb out I saw fuel come out in climb but we never smelled fuel in the cockpit. Therefore check the fuel lines especially the vent lines on the tank you were using when you smelled the fuel. At Oshkosh one year I was working POP and someone stopped me about fuel coming out the vent line.s of an airplane that had just been refueled. When I looked at it (RV-6A) as I recall fuel was coming out of both vent line holes from the expansion. Therefore that would be my best guess.

hydroguy2 · Post by **hydroguy2** » Tue Dec 21, 2010 10:54 pm

unable to locate any blue stains or wetness, so put everything back and shoveled snow from in front of the hangar door. Launched this afternoon for another test. No fuel smell noted....I'll still be vigilante looking and sniffing for a while.

Took Aurora to KHLN about 26nm miles away. Did some 2 way runs while running the engine 23" 2450rpm. averaging 175kts. wooohoo! Everyone at my old FBO where I got my license 5 yrs ago came out to oh & aw. Lot fo thumbs up and atta boy's.

Eight miles out I got told by the tower to slow up a bit for spacing with a Dash-8 commuter. 218mph GS ain't too shabby

When I got back, I overflew the paint shop. Corky happened to be outside at that moment. waving at me so gave him a big wing rock and set up for a return trip at 700'agl and about 210mph. As I went by, I lowered a wing for all to get a good look, next leveled out before pulling into a >4000fpm climb. After I put her back in the nest I stopped by to talk, those guys were pumped up. Said it was fantastic to see her zoom by and she sounded awesome. Corky wants to go into the custom aircraft paint business.

cjensen · Post by **cjensen** » Wed Dec 22, 2010 8:32 am

You've got something very special up there in Big Sky Country Brian! So happy to hear you're enjoying the living daylights out of it!!

Brantel · Post by **Brantel** » Wed Dec 22, 2010 10:22 am

Nice, very nice!!!

BSwayze · Post by **BSwayze** » Wed Dec 22, 2010 10:43 am

GREAT picture, Brian! Way to go!!

Bob Barrett · Post by **Bob Barrett** » Thu Dec 23, 2010 3:13 pm

Good picture of the airplane Brian! Glad you are enjoying it

You friend who painted it does a good job but his location may deter some people form using him! I hope the feul smell is gone permantly! Have a Merry and Blessed Christmas and a Happy New Year! I look forward to meeting you and Lance in Person in 2011

hydroguy2 · Post by **hydroguy2** » Thu Dec 23, 2010 6:35 pm

Bob Barrett wrote:.........but his location may deter some people form using him! .....

I told him that might be a problem, but he is planning on slowing down, so wouldn't schedule anything during the winter. During the spring-fall, people might even want to come here and do a Montana Vacation while their plane gees painted.

Merry Christmas to you also, we'll meet in 2011

put another hour on her today and no fuel smell