engine and drivetrain Dual DCOE tuning with Vac Gauge

[SpetzNaz]

Trying to tune my dual DCOEs and notice that when vacuum gauge is connected it bounces very quickly between 0-15inHg at idle. When I increase the engine speed the gauge goes steady at around 5inHg. The higher speed reading seems ok to me but I am not sure what to make of the idle reading.

Also at higher engine speed i hear some back firing but that's probably due to low energy spark? need to switch to electronic ignition with a little more power in the coil?

Any ideas/thoughts would be appreciated.

Thanks

[Lee]

Any ideas/thoughts would be appreciated.

Good quality vacuum gauges have an adjustable restrictor that allows to avoid spikes at low RPM. Your backfires are most likely caused by lean condition.

Lee

[c.d.iesel]

check valve adjustment (cold) - yours are too tight

0.006" ....0.008"

[SpetzNaz]

Valve adjustment has been checked i am between .006 and .007 in the cold condition.... What problem would be cause by too small a gap?

Thanks,