I have a problem getting the air duct tube back on the carb air intake when I remove my lower cowling. I ordered a replacement air duct tube from both Univar and Aircraft Spruce. Both were very light and flimsy. I have been installing the tube on the cowl duct using one clamp as specified in the parts manual. When I try to get it to mount on the carb intake it deforms and will not slide on. Is there a tube of different composition that does not deform like these light weight jobs? Any "tricks of the trade" on getting these things on easier?
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Air duct tube
- Thread starter lcoriell
- Start date
I've replaced mine with the one ACA sells and had no issues with it. One thing I did notice is you have to be careful and not get the band clamp overly tight. It just needs to be snug, or it will simply slide off the fiberglass. Then install the cowl with with the air filter removed and you can adjust the duct to the outside of the carb intake. I don't think there is any way to avoid taking the air filter off to make the final adjustments to duct so its outside the intake.
The duct should be a bit loose around the carb intake since it will be held tight around the carb intake by the engine suction during operation. You will find lots of people with this on backward (the tube clamped to the carb intake instead of the cowl), but that's asking for trouble if the tube slips off the cowling inflight in that configuration (I was told there is a potential for it to get sucked into the carb and stop the motor).
Paul
The duct should be a bit loose around the carb intake since it will be held tight around the carb intake by the engine suction during operation. You will find lots of people with this on backward (the tube clamped to the carb intake instead of the cowl), but that's asking for trouble if the tube slips off the cowling inflight in that configuration (I was told there is a potential for it to get sucked into the carb and stop the motor).
Paul
Paul and Tom, thanks for the info. I have the the round Brackett BA-106 filter assembly (uses the BA-11 filter). Not sure I can get a hand through there to move the duct but rolling it back sounds like a winner. I have spent a lot of time wrestling the lower cowl ; I should have asked sooner.
Lynn
Lynn
Find a buddy to help, one on each side, and fight. Prepare the area but remove young ears, for the onslaught of cussing. know that your shoulder muscles will fatigue, but if you stick to it, the cowling will give in. Make very sure everything that is on,in,around that engine is ready to be covered up, because you dont want to do this again until next year.
I have the same ba-11 filter as you, there is no reaching in there. I like that roll technique, I'll try that NEXT year.
I have the same ba-11 filter as you, there is no reaching in there. I like that roll technique, I'll try that NEXT year.
FYI-
I have a 2001 7GCAA and it is quite easy to lay on a creeper and reach up to roll the duct back over the carb heat box, I replaced the duct around 500 hours to keep it snug. When I'm on the creeper I use a flash light to confirm the cowl/baffle seals are in place and a long paint stirrer to push them into place if required.
CAUTION, the duct MUST be clamped to the cowl NOT to the carb heat box, there have been cases of ducts clamped to the carb heat box being sucked back into the heat box and cutting off airflow.......................
Tom-
I have a 2001 7GCAA and it is quite easy to lay on a creeper and reach up to roll the duct back over the carb heat box, I replaced the duct around 500 hours to keep it snug. When I'm on the creeper I use a flash light to confirm the cowl/baffle seals are in place and a long paint stirrer to push them into place if required.
CAUTION, the duct MUST be clamped to the cowl NOT to the carb heat box, there have been cases of ducts clamped to the carb heat box being sucked back into the heat box and cutting off airflow.......................
Tom-
How do you tighten the clamps on both? Once the cowling is on, the're pretty much impossible to get to, at least on my plane.
By the way, I very much appreciate this post. I checked my Decathlon, and the clamp was incorrectly on the carburator, not the fiberglass duct. I checked the Decathlon service manual to confirm where it should be. The only thing I could find was in the parts manual where it did show the clamp on the fiberglass cowling, not the carburator, so I corrected mine. I don't know who or why they get changed around, but this could be a significant safety issue.
Is there anyone from American Champion monitoring this board? If so, can you please weigh in on this?
SamS
By the way, I very much appreciate this post. I checked my Decathlon, and the clamp was incorrectly on the carburator, not the fiberglass duct. I checked the Decathlon service manual to confirm where it should be. The only thing I could find was in the parts manual where it did show the clamp on the fiberglass cowling, not the carburator, so I corrected mine. I don't know who or why they get changed around, but this could be a significant safety issue.
Is there anyone from American Champion monitoring this board? If so, can you please weigh in on this?
SamS
Sam-
The 7 series Service Manual is likewise vague, the Parts Manual shows it correctly but it would be easy to overlook. I suspect improper clamp placement is another entry in "The Journal of Unintended Consequences", someone thought it would be easier to install clamped to the heat box and didn't think about the ramifications.
Given that ram air will cause a slight bleed around the aft end of the duct and heat box there is no concern about sucking in unfiltered air and therefore no reason for two clamps.
Tom-
The 7 series Service Manual is likewise vague, the Parts Manual shows it correctly but it would be easy to overlook. I suspect improper clamp placement is another entry in "The Journal of Unintended Consequences", someone thought it would be easier to install clamped to the heat box and didn't think about the ramifications.
Given that ram air will cause a slight bleed around the aft end of the duct and heat box there is no concern about sucking in unfiltered air and therefore no reason for two clamps.
Tom-