-----Original Message-----
From: spitfires-owner@autox.team.net
[mailto:spitfires-owner@autox.team.net] On Behalf Of David Mayer
Sent: Tuesday, May 18, 2004 10:34 AM
To: Spitfire
Subject: Tuning carbs question...
I started my '68 Spit Mk3 with dual Su's up ther other day and tried
tuning
them. However, nothing seems to be working! I have the tool that you
place
over the intake and the little ball inside goes up. When i placed it
over the
front carb, the ball goes all the way to the top. When the toll is over
the
rear carb, the little ball stays down at the bottom.
What am i NOT doing that would get these to sync up? The engine still
runs
decent but not as smooth as it could be. Any suggestions?
Thanks,
David
David,
It is very important to have the carbs balanced as much as possible
before you start. The closer they are, the easier it is to fine tune
them.
The Haynes manual has a great procedure for adjusting them, but here is
what I do.
1. Be sure to loosen the clamps that secure the linkages together so the
carbs are independent.
2. Adjust the Uni-Syn so that the ball only goes up about half way on
the carb that has the greatest movement.
3. Adjust the idle screw on the carb with the least deflection until the
ball deflection is equal to the other carb.
4. Tighten the clamps on the linkage so that the carbs are operating
together.
5. Adjust the idle screw so that the engine is idling at the desired
prm.
6. Continue with the other adjustments for best performance.
Joe
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