mixture cable

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8369
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mixture cable

Post by 8369 »

I have noticed that my mixture cable is disconnected on my NA-S3A1 carb(C-85). Can I just reconnect the cable so i can use it to shut off the engine and keeping the engine from being over rich?
thank you.
4390
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Re: mixture cable

Post by 4390 »

There's lots of information in the technical articles on Stromberg carbs. They cover the questions you're asking.
6277
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Re: mixture cable

Post by 6277 »

Short answer is no. My mix cable is connected. I have never used it to lean during flight although some have at high altitudes. I shut off the fuel and let the engine die naturally for shutdown. If you turn the mags off to shut down, a lot of fuel will be sucked into the cylinders before the engine stops rotating. I'm told this will wash the oil film from the cyl walls and might cause corrosion. My .02 worth.
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Re: mixture cable

Post by 6183 »

Hello Edward,

I've seen mixture levers on the Stromberg carburetor wired in the full rich position with no cable attached, and I've also seen them attached to a cable so that they can be operated from the cockpit. On my first airplane that I had in in the early 70's (Luscombe 8-E) which had a C-85, the mixture lever on the carb was wired in the full rich position and therefore, could not be operated from the cockpit while the engine was in operation. Curious as to why so, I inquired with my A&P IA at the time who explained that the mixture control on the Stromberg does not work like that on a Marvel Schebler carburetor. With the Stromberg, pulling the mixture control out to lean will not shut the engine down when on the ground. The principle on the Stromberg he explained is based on a series of plates with holes that need to line up in order for the unit to work properly, and does not shut off fuel to stop the engine as with the Marvel Schebler design seen on the 0-200. Most manuals for aircraft equipped with the Stromberg mention to use the mixture control when above 5,000 feet. I believe my fellow moderators Victor Grahn and John Cooper have talked about this in the past on previous posts, and may be able to add more information than I'm posting here.

It's your choice to either run the engine without having the mixture control attached to a cable for control or just leaving it in the full rich position. It will interesting to see what others post on this subject.
6183
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Re: mixture cable

Post by 6183 »

6277 wrote: Wed Mar 27, 2019 9:41 am I shut off the fuel and let the engine die naturally for shutdown. If you turn the mags off to shut down, a lot of fuel will be sucked into the cylinders before the engine stops rotating. I'm told this will wash the oil film from the cyl walls and might cause corrosion. My .02 worth.
I've heard that procedure also. I've always used the procedure of shutdown on an engine equipped with a Stromberg by shutting off the mag switch, and at the same time pushing the throttle to full open as the engine rotates to a stop then pulling the throttle to the closed position after rotation stops. An older A&P told me years ago that method which he explained purges the intake system of fuel to prevent an inadvertent start if someone moves the prop and doesn't check to see if the mag switch is on or off. Either procedure will work however, I may be doing it incorrectly. Interesting to find out. Anyone have more information on the subject?
8369
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Re: mixture cable

Post by 8369 »

Thank you everyone, this is great info. I have been shutting down by turning off the fuel. I will just keep it wired up for now and just keep flying. thanks again. :)
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Re: mixture cable

Post by 6298 »

Above 5000 feet it does lean for smoother operation and more power for takeoff. It doesn’t have the idle cutoff like the Marvel, but you can shut down by going full lean, and advancing to full throttle.
Randy Thompson A&P IA Pilot
Hold STC SA547EA for installation of O-200 engine in Cessna 120/140 and 140A"s
Overhaul small Continentals
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