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Old 01-23-2018, 02:43 PM   #8
Dead Parrot
Registered User
Join Date: Aug 2012
Location: Oklahoma City, OK
Posts: 1,885
Re: I feel something is off with my new engine.

Was that 12* initial timing with the vacuum advance disconnected? (supposed to be.)

If you just have a basic timing light and a tach, you can do a check on your mechanical advance curve.
For testing purposes: Disconnect your vacuum advance and plug the carb hole. Set your initial timing to TC, zero advance. (engine probably won't like it). Watch the tach while you slowly rev the motor. Note the RPM when your timing starts advancing off Zero. Keep speeding the motor up. There will be a point where more speed quits giving more advance. Note this RPM.
You now know when your mechanical starts, ends and how much you get.
Reset your initial timing back to normal.

Discuss your results with your engine builder. He may suggest recurving the mechanical advance. There are low cost kits for that.

Vacuum advance is for part throttle driving and economy. Has no impact on full throttle power.

Get your timing working correctly first, then play with the carb. On a non-emission motor, you usually want as much advance as you can get without knocking/pinging.
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