Hi All:
I have an os46ax given to me by a friend. Took it to the field today, in my plane,and started it up. Started just fine, tried to adjust the hsn, but it would make no difference. Tried the pinch test, through the whole needle range, held the plane nose up, wanted to die in that position in various settings. Have never flown this engine, it is not a new engine. Can anyone tell me why I can't get a change with my needle adjustment? It sounded like it had plenty of power and transitioned really well, but as soon as I held the planes nose up, it wanted to die, couldn't do the pinch test either, did not speed up when I did this either. Could there be a leak?

thanks for your input. I know there is someone out there who has a solution.
Norm

Sounds like crud in the carb. Pull the needel out and hook up a fuel pump to the carb and try back flushing as a first step. If that doesn't work it could be a few other things but back flushing is a good place to start.

Sounds to me like an air leak if it wants to lean out on nose up and die. If it still acts up after the carb cleaning, change the needle o-ring.

there is some things to check, lines for leak, close the needle and re opened again...try to use a tach to get peak rpms and try again.

You might also look up the manual on the 'net. I bought the same engine. The old pros at our field said the same thing that you did. It turned out that the starting point for the AX was, maybe, 1 1/2 turns. They started tuning it at 4 or 5 turns...and never got down to 1 1/2 turns......They thought 4 or 5 turns was correct since since the FX was set that way. When we started all over with the factory settings, everything worked just fine. Rich

Thanks guys, going back out today, will try these. Knew I could count on you.
Norm

Just to go over the obvious.....

The HS needle settings for the most part manifest when the throttle is over 70% or so. To see the changes created by adjusting the high speed needle you need to run your engine at WOT.

I typically restrain my plane, run it up to WOT and adjust the needle while the engine is running.

Have you tried this?

check and make sure both of the screws holding the carb to the case are still there.