[snbush67]

Start by warming the motor up.

Turn the motor off.

Start by documenting where each air screw and mixture screws are set at.

Turn each mixture screw in, counting turns in, write each down. Turn each mixture screw in until it seats (gently, don’t over tighten), then back out 2.5 turns

Turn each air screws in, count the turns and write it down, leave the locking nut loose until tuning is complete.

Turn each idle stop screw out until you can see a gap, then turn it in 1/4 turn.

Start the engine.

Adjust throttle stop screws equally until the engine idles at 1000 rpms.

Remove linkage short arms on both carburetors.

Using a synchromter, measure the pull of each cylinder it should show around 5-6. Note each cylinder.

The next step is to balance each bank of carbs.

Using the air screws adjust each 123 cylinder to match the the highest number cylinder in the 123 bank of cylinders.

Next Using the air screws adjust each 456 cylinder to match the the highest number cylinder in the 456 bank of cylinders.


Next step is to balance left to right.

That’s simply using the synchrometer to match the 123 back to the 456 bank.

Check engine rpms, adjust the idle screws equally to get the engine idle down to 900.

Attach the 123 throttle linkage, ensuing the is no change to rpm’s. Then attach the 456 throttle linkage, again ensuring there is no change to rpm’s, you may have to shorten or lengthen the short linkage arms to be equal.

Now adjust the mixture screws for best lean.