5 replies to this topic

[cal844]

I have a standard 998 in my Estate

Currently has a stage one kit(AAU needle, standard type KnN filter)

65D(1990 onwards carb car dizzy)

Runs well but is very rich

9% CO with the nut fully lean... Can anyone suggest what needle is best to try?

Thanks all and kind regards!

Edited by cal844, 15 May 2017 - 08:06 PM.

[Boycie]

Is the float chamber flooding?  I'm surprised it's still so rich with the jet wound all the way up..

[panky]

It could be a worn jet. Try dropping the needle carrier a little bit and see what happens. 

[cal844]

Is the float chamber flooding?  I'm surprised it's still so rich with the jet wound all the way up..

Not flooding, I changed the float (pivot was sheared off) and cleaned the float valve, it has a new tank and all new pipes with an inline filter too

Panky, what part do I need to adjust?

[panky]

Take the piston out and loosen the screw that locks the needle carrier in place, initially the carrier should be flush with the bottom of the piston. Once the locking screw is loose pull gently on the needle and the carrier should start to come out, try locking it up again with the carrier about half a millimeter proud of the bottom of the piston, this will allow the needle to sit lower in the jet and give you a bit more adjustment on the mixture - you shouldn't need much to make a difference.

The first MOT after the last time I rebuilt my engine the CO2 was way high and wouldn't adjust out so the MOT man took the top off the carb dropped the carrier slightly and passed it, very nice man

[cal844]

Take the piston out and loosen the screw that locks the needle carrier in place, initially the carrier should be flush with the bottom of the piston. Once the locking screw is loose pull gently on the needle and the carrier should start to come out, try locking it up again with the carrier about half a millimeter proud of the bottom of the piston, this will allow the needle to sit lower in the jet and give you a bit more adjustment on the mixture - you shouldn't need much to make a difference.
The first MOT after the last time I rebuilt my engine the CO2 was way high and wouldn't adjust out so the MOT man took the top off the carb dropped the carrier slightly and passed it, very nice man

Ah yes, now I know the name, I usually set it so the carrier is flush with the piston, I will try adjusting it though!