Os Max 40 Sr
12-08-2002 | 06:11 PM
#1
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From: Phoenix, AZ.
Os Max 40 Sr
I have an OS MAX 40 SR that is new in box but, I dont have the stock needle positions for a starting point for tuning. Can anyone help?? Would be greatly appreciated!!
Chris
Chris
12-10-2002 | 07:44 PM
#4
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Os Max 40 Sr
Chris,
The O.S. Max #4B cvarb is an oldie, but the design is still in use in the modern engines.
You basically set the idle mixture by turning the screw (in the center of the throttle arm) clockwise unitl you see the brass shoulder start to intrude into the venturi. If you turn it too far, you'll see the black o-ring. When the shoulder protrudes into the venturi, back it out until it's just fluxh or below flush. That's the starting point.
Get the engine running and adjust the high-speed needle first. Then retard the throttle and work on the low end.
We'd suggest an APC 10x6 prop on your engine to start with, but don't be afraid to play with different props to see how the engine/airplane combination works. Your engine can safely turn as high as 13,000 RPM without worry.
The O.S. Max #4B cvarb is an oldie, but the design is still in use in the modern engines.
You basically set the idle mixture by turning the screw (in the center of the throttle arm) clockwise unitl you see the brass shoulder start to intrude into the venturi. If you turn it too far, you'll see the black o-ring. When the shoulder protrudes into the venturi, back it out until it's just fluxh or below flush. That's the starting point.
Get the engine running and adjust the high-speed needle first. Then retard the throttle and work on the low end.
We'd suggest an APC 10x6 prop on your engine to start with, but don't be afraid to play with different props to see how the engine/airplane combination works. Your engine can safely turn as high as 13,000 RPM without worry.
