Unfortantly very rich and very weak will give an almost identical effect. Neither will pull away well but both will rev free with no load.

What you need to do billy is take it for a ride and get it warmed up. As you coem back to your house stop. Try and pull away but dont let it get into the sweet zone, make sure it splutters and coughs or what ever it does. Kill the ignition and pull a plug out. This ISNT a plug chop but even at low RPM's under load a plug shouldnt be too black and oily. If the plugs are soaking wet.. like dripping then it is rich. If they are black but dry youre weak. You wont get a brown center either way as it hasnt had time to change colour. This shoudl give you a clue which way you need to head.

Once you have decided weather its right for weak we can decide what to do to fix it.
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If I have to take the carbs off once more...