Since my wifes 1985 escort was motted ,it has been sick. I suspect they have damaged the carb mixture screw as the co analyser readout is extremely low . The engine revs go up and down every second and screwing in the mixture screw (VV carb) makes it worse . Haynes says screwing the mixture screw weakens but is hunting cause by a rich mixture?.The plugs are getting sooty also. I have put in a new cb and checked timing. ? thanks for any light on cause of hunting
Steve
I don't know the VV carb, but sooty plugs plus hunting suggests wrong float level. Is the needle valve clean, free to move, without crud on the seating? Is the float set wrong or sticking? Is the air filter dirty or clogged - or wet. Is the mixture screw cross-threaded?
Start by assuming that the mechanic tried to correct a mixture error for the exhaust test and mucked something up. Go through the manual and see what he might have changed.
Jim
Check the diaphragms - they're notorious for splitting.
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