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Old 04-15-2007, 01:17 PM
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Ken Talbot Ken Talbot is offline
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Join Date: Jun 2002
Location: Revelstoke, BC
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ADJUSTING PILOT SCREWS BY EAR vs. COLORTUNE

Tuning is a bit of an interactive process at the best of times. You may have to sync first, adjust the screws, then sync again, etc. Try starting at two turns out from lightly seated:

  • - warm up the engine and sync the carbs with a mercury tool or vacuum gauges

  • - adjust the idle down to approx 700 or 800 rpm

  • - adjust one pilot screw out slowly while listening very carefully to the engine sound and watching the tach needle

  • - listen for the engine speed to pick up a bit then fall off

  • - if it doesn't pick up, adjust the screw slowly in, again listening for any increase in idle speed

  • - when you her the increase, adjust past it a half turn or so, then come back to it again until you've got the sweet spot

  • - adjust the idle speed back down to your low starting point

  • - then work another screw, again looking for its sweet spot

  • - each time you get a screw adjusted, drop the idle back down

  • - once you've got all four screws set, resync the carbs

  • - take one more pass through the pilot screw adjustment for each carb, still working at 700 to 800 rpm
    verify that the sync still looks good

  • - adjust the idle back to 1100 or so depending on your personal preference



- go for a ride!
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Ken Talbot