How to Find Source of Fuel Smell?

[John-G]

Originally Posted by Piper J3

Question... Does anyone know the weight of a set of new floats fresh out of the box?

Jim - not sure about of the box, but I checked the weight of both the floats in each carburetor on my engine prior to installing it on the RV-12 firewall. The floats measured in at 3 grams each.

Since you are in the carbs .... make sure the float arms are parallel with the body of the carb when the carb is held upside-down. It is possible for otherwise good floats to allow excess fuel into the carbs if the float arms are also not adjusted correctly. Visually, they should be parallel ... but there is an $85 gauge that is supposed to be used to make the adjustment perfect.

[DHeal]

Originally Posted by Piper J3

Question... Does anyone know the weight of a set of new floats fresh out of the box?

Mine were 2.8 grams dry each out of the box (i.e., 5.6 grams total for the pair).

[daveyator]

3 grams is about 1/9 of an ounce. Sounds a bit light to me
Cheers,
DaveH

[DHeal]

Oooppss! I should have said 2.8 grams each! 5.6 grams total.

[daveyator]

Set my mind at rest. Thanks.
Cheers
DaveH

[Piper J3]

Thank you gentlemen...

[Bigsteve]

I had the same smell on climbout only. Removed the tunnel cover and found real small leak on blue fitting used to connect fuel return line. I had been using some avgas, so trail to fitting was obvious. A & P added microthin washer to fitting and all good. My guess is that during climbout, the gas moved down the tunnel to where the fuel shut-off is and a small opening exists where the handle comes thru that also allowed the vapor to exit. Never smelled gas during long flites, or taxi or landing, only on climbouts. This happened during the time period when we were weighing floats, waiting for new ones, so i thought the smell was float related also.

[Piper J3]

Update... I bought AC Delco 10-5045 Multi-Purpose Fluorescent Leak Detection Dye and 100 LED UV Black Light Scorpion Flashlight to help locate source of fuel smell. Yesterday I mixed 1 oz. of the dye with 12 gallons of fuel in the tank and flew for half hour. Today I will open all access panels and search for source of leak with black light. The dye fluoresces a brilliant orange color so it should be easy to spot a leak.


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[RFSchaller]

Good luck. I just did the 5 year hose replacement, and I am chasing a coolant weep that equates to 1/2" of overflow bottle level in 12 hours of operation. I put The dye in my coolant Friday and will check with a UV light Monday after 5 hours of flying this weekend.

[Piper J3]

Found the leak with black light and fluorescent dye... works a charm. Two flush rivets at internal strengthening plate on front bottom right side have very slight (miniscule) leak. Real problem is single rivet on top cover plate in rear right corner has enough seepage to wet your finger when you wipe over it. This rivet is leaking when the plane is in a climb and fuel sloshes to the rear.

I also removed cowling to check carb overflow. They are dry as a bone...


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