National Aeronca Association Bulletin Board

What is the function of the 3/4 " hole in the air box lid left side directly above the carb heat lever? Also directly below the carb heat lever is a spacer perhaps 13/16" long, what is the purpose of this?

Thanks much

Paul
N83803
N1431A
2AZ1

The hole is so you can get to the carb bowl drain on a Stomberg (maybe a Marvel) without having to remove the airbox. The bowl needs to be drained and checked for debris every annual. Not sure what the spacer is you're talking about. Got a picture?

nkh

Here it is. The drawing calls it a bushing. It's the post just under the arm.

that's a new one for me. Most have some sort of bracket on the left rear corner to attach the carb heat cable. I've seen them both riveted and screwed to the box. I might have a pic on the other blackbox.

nkh

Isn't there some kind of a spring that hooks from that bolt to the carb heat lever?
I can't remember if it's original or not though.
Mike

I got an answer on the fAA mailing list. A spring goes there to keep the flapper from flapping in case the control wire breaks.

The hole became apparent as soon as I brought the airbox within a foot of a carb.

Cheers:

Paul
N83803
N1431A
2AZ1

Well I learnt somethin new today.

nkh

I also learned something. My cable will drift open a little during flight. I'll put a spring on it.

But wait, on second thought, will a spring not cause drift in the opposite direction?

Thanks, Dennis

The spring will hold it either open or closed, but not in the middle because of the over-cam nature with a spring setup. An alternative to stop it creeping; with it in the cold position put a very slight bend in the cable with a pair of pliers. That will create a "detent" where the inner cable will nest with the sleeve. And it will add a little bit of tension on the cable when in partial or hot position. Had to do that to both Champ and Cub.

nkh

Thanks Nathan

Dennis