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Old 10-13-2008, 06:17 PM
Randy Rosenberg Randy Rosenberg is offline
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Join Date: Jul 1999
Location: SF Bay Area, CA
Cobra Make, Engine: SPF #1019
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Quote:
Originally Posted by Terry Stapley View Post
The problem was when cruising and VERY slowly rolling into the throttle. If you push on the go pedal quickly - no issues!
What is different is it seems down on power after advancing the timing, but the stumble went away!!
Weather permitting I will back off the timing and as Warren suggested richen up the idle circuit a tad to see if that helps. I also will install new spark plugs and report back!!
This tip-in stumble sounds to me like a lean condition. You seem to confirm this by advancing the ignition to make the problem go away. Lean fuel burns more efficiently with greater advance (pump gas is designed to burn this exact fashion, which is why modern vehicles get better MPG - the compooper leans out the fuel and advances the ignition).

Richen up the idle circuit and/or install a more agressive pump cam and/or install a slighter larger squirter, so that you get a richer squirt at tip-in.

Good luck,
Randy R...

Last edited by Randy Rosenberg; 10-13-2008 at 06:46 PM..
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