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Not wanting to completely disassemble a new Aeroinjector unless I have to, how much movement should there be between the needle and slide, if any? No way for me to measure, but there is noticeable movement, both rotationally and longitudinally. I would have thought the needle should have no movement in relation to the slide.

I have used the aero carb on my Jab 3300 in 2007 and now the aero injector on my Aerovee turbo currently flying. It has been my experience that you are able to "wiggle" the needle a little bit by reaching into the carb throat. I think this is normal. The needle is not likely designed to be a "tight fit" in the fuel orifice.
I would assemble the unit according to the manual, install it, verify that the slide itself does not bind throughout its intended range of motion, and then follow the manual for tuning. Initial tuning is a source of frustration for many of us and for many others, it is not even a blip. We all go through it in the initial hours. Go figure. Hopefully, yours is the latter.

Lou Pappas
Waiex B 0010

The needle sometimes moves rotationally. To prevent that many of us have lightly peened the threads on the needle carrier. It's also my experience that turning the set screw to tighten it can turn the needle. So whenever I set the set screw I did two things: 1. I reach into the carb orifice and use a thin Sharpie to mark a line where the needle meets the carb body. This way you can see if anything moves. 2. Hold onto the needle with your fingers while tightening the set screw, to prevent the needle from turning. After the set screw is tightened verify the needle has not moved by observing the Sharpie line on the needle. After tuning, I have not touched my needle in nearly 6 years.

Area 51% wrote:Not wanting to completely disassemble a new Aeroinjector unless I have to, how much movement should there be between the needle and slide, if any? No way for me to measure, but there is noticeable movement, both rotationally and longitudinally. I would have thought the needle should have no movement in relation to the slide.

The needle is mounted in the square needle holder block. Small movement side to side is normal. But longitudinal movement is not good and was caused by the ball joint of the adjusting screw having too much clearance in the needle block. Mine had nearly a half a turn worth of play. That's a lot of movement when tuning. Tighten it up with shims or whatever why you can. I actually had a new screw and needle holder made with a sloted disk rather than a ball resulting in zero longitudinal play. Onex 107

So what threads get peened? The little set screw that traps the needle, the adjuster threads, or the setscrew that locks the carrier in place?

Area 51% wrote:So what threads get peened? The little set screw that traps the needle, the adjuster threads, or the setscrew that locks the carrier in place?

I peened/squished the threads on the adjuster needle screw, since that's the screw I don't want to move once it's in place. The set screw then locks up that peened adjuster screw.



I followed the same process Mike used to make sure/verify the needle didn't move as I was tightening the set screw.

http://www.rynoth.com/wordpress/waiex/2 ... le-issues/

I had better results putting a 3/16" ball bearing between the needle carrier and the set screw. The ball does not impart any turning force to the needle carrier when you tighten the set screw.

Looks like another item on the "fix it before you dare use it" list.

Putting on my "scrubs", preparing for an Aeroinjector autopsy here @Area 51%

Took Chett (airplane's name) for his first taxi test this morning, and thought something had jammed in the throttle linkage as it was quite difficult to get the lever to move. Didn't want to break something, so I shut down to investigate, only to find the throttle operating smoothly with little friction. A restart resulted in the same sticky throttle movement.

I know I read somewhere about the slide not wanting to move as freely when the engine is running because of the suction. What I don't remember is if there is a cure?

No longer having to make "fake" engine sounds while sitting in the cockpit here @Area 51%

[quote="Area 51%"

I know I read somewhere about the slide not wanting to move as freely when the engine is running because of the suction. What I don't remember is if there is a cure?
[/quote]

Are you using an older AeroCarb with the push to open slide? If so, the cure is using a new Aeroinjector which is a greatly improved version of the carburetor with a pull to open slide and other significantly better features.

Art,,,,,,,,,,,,,,,,,,,,,Sonex taildragger #95,,,,,,,,,,,,,,,,,,,Jabiru 3300 #261/AeroInjector (latest version)