[Roadsters] Leaning out the carb

[Pat Horne]

David,

Some questions, and some possibilities.

Did the car start when warm before your rebuilt the carbs?
When you say that the Roadster starts fine when cold, is that with the 
choke knob pulled or in?
Did you synchronize the carbs after putting them back on?
If you watch the carb pistons when the engine is running, both at idle 
and when advancing the throttle, do both pistons rise the same amount?
If you lift the pistons with the engine off do the both make a click 
when they bottom out, or do they stop before they get all the way to the 
bottom? If they don't, the jet on that carb needs to be centered.
Are the shoulders on the needles sitting flush with the bottom of the 
pistons?
Have you verified that the carb float levels are correct? The fuel 
should be just below the top of the jets

There is a piston lift pin on each carb. With the engine running when 
you press up on the pin on one carb, the engine should slow down, but 
continue to run. Try the same on the other carb and it should slow down 
about the same. If they don't match, the carb synchronization is off.

If lifting the carb pistons helps it to start better, then you are 
enrichening the mixture, not leaning it out. There is only one mixture 
adjustment on each carb, the knurled knob around the jet on the bottom 
of the carb. The way to adjust the mixture at high speed vs. idle is to 
change the needles. Turning the knob CCW from the bottom of the carb 
enrichens the mixture.

Check the mixture to be sure that it is set correctly, I use a wide 
range O2 sensor on a piece of exhaust pipe that I insert in my tailpipe 
connected to a digital voltmeter.

Peace,
Pat


Thusly spake David Boerst, On 5/27/2010 2:47 PM:
> My gals' 1966 Roadster is a bear to start when hot. If I lift the choke pistons it starts easily. I overhauled the carbs and did a excellent job, meaning soaked them in carb cleaner, washed them in hot soapy water then clean water and blew them and passages completely dry. Use all new needles, jets etc. The car runs great when its running. Starts first try coold. Timing is correct. How do I lean it out or what else could be done. Thank you everyone who has commented before!
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-- 
Pat Horne, Owner, Horne Systems 
(512) 797-7501 Voice		5026 FM 2001
Pat at HorneSystemsTx.com	Lockhart, TX 78644-4443
www.hornesystemstx.com
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