Adjustment of 503/582 CArburetors

[Aviation Engines]

I had a request on the SAMicro newsgroups for this information, herewith my response.


Check that the jetting in the carb is correct.

503
Jet Needle 11K2 - Circlip position #2 from top
Needle Jet 2,70
Main jet 158 at Sea Level
Main Jet 150 at Highveld Idle Jet 55

582
Jet Needle 11G2 - Circlip position #3
Needle Jet 2,72
Main Jet 165 at sea level
Main Jet 158 at Highveld
Idle Jet 45

Make sure that the needle circlip is below the plastic spring holding cup and NOT ABOVE

Turn big idle adjustment screw completely out until it no longer makes contact with the piston. Make sure that the piston is completely closed (down) and not hanging on the cable.

Turn the idle screw in until the piston rises by about 5 mm, make sure that both pistons are at the same height.

Turn the idle air adjustment screw completely in and then 1 1/2 turns out.

Open the throttle (engine off) and stop when the bottom of the piston just meets the top of the port. Make sure that both pistons are at the same level, this can be adjusted at the adjustment screw through which the cable goes.

The throttle cable should have approx 1mm free play at idle.

Also check that the choke cables have the same free play when closed.

Start the engine and get it up to operating temp. Adjust both idle screws equally to get an idle of 2000rpm. You may fine tune the idle air adj. screws if necessary to try and get it running smoothly.

Adjustment of the float lever - remove the float chamber and the float lever should be parallel to the float chamber edge, adjust by being the part that activates the float needle valve.


Regards
Niren Chotoki
Aviation Engines & Accessories (Pty) Ltd

[DarkHelmet]

I wish we had a way to keep all these valuable posts tidy and together. How about pre-fixing it with TECHTIP - ?

Thanks much Niren!

[vincent]

How about some more of these tips!