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Old 11-25-2007, 05:45 PM
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Jac Mac Jac Mac is offline
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Join Date: Feb 2006
Location: Gore. New Zealand., SI
Cobra Make, Engine: DIY Coupe, F/T ,MkIV.
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OK, so you have tried two jet combos in the car with same problem-------- Are you sure that it is not an ignition curve problem with all the advance arriving at that 2500 approx rpm point or perhaps a 'sticky' advance mechanism. Hook your timing light up & run the rpm up thru the range, the advance should be a gradual advance with RPM, not a sudden increase of say 10°/15° in 500rpm. You must try and have a reasonable curve plotted before attempting to rejet. Heat range , Rotor Phase , Incorrect MSD wiring and a possible cross-fire from plug leads are other things that might be worth looking at as well.

Detonation is going to kill it quick so try to nut the problem out with minimal engine use- look hard & re-examine everything you have done prior to the problem- lot easier to live with than the problem coming out to meet you.

Jac Mac
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