alternate air door

[DonMuncy]

The alternate air door on my 231 has decided to remain open. There appears to be a little friction when it gets almost closed, and the cable (wire) can't push it shut.

I am tempted to ask my hangar elf to attach a magnetic device to assist in holding it shut, as I understand some models have.

Any ideas.

[N201MKTurbo]

My M20Turbo intake has a magnet to hold the alternate air door closed. The magnet appears to be straight from the cabinet isle at the ACE hardware.

the magnet is pretty strong. The door is blown closed by normal air flow. If the filter ices over, it will suck it open. I check it every year, but never functionally. I guess I could put masking tape over the filter and start the engine and run it up and see what happens.

[carusoam]

Magnets have been known to lose strength over time…

It probably is an easy swap with a new one…

Best regards,

-a-

[MatthiasArnold]

At least for my Ovation 2, I have to readjust the air-gap between the magnet and the alternate air door from time to time .. (very seldom)

• Symptom: With WOT/high RPM operation close to sea level (e.g. during take-off run) the alternate air door opens automatically due to "suction" in the manifold (although the air filter is in good condition). The door closes automatically (through gravity) once power and thus suction is reduced.
• Root cause: Magnetic flux and thus holding force reduced, mainly through a (widening) small air gap between magnet and door
• Solution: The magnet is attached with two Philips screws. Loosening the screws allows for moving the magnet. At least for my installation loosening the screws, sliding the magnet all the way to the door in its closed position (air gap close to zero) and re-tightening the screws fixes the problem. The service manual states a reference value for the holding force.

Best regards,

Matthias

[geoffb]

The 252 alternate air door is held shut with a magnet.  I think the alternate air assemblies are quite different though between -LB and -MB, so not sure what you could adapt to yours.