3 replies to this topic

[minirock]

Model:myfair 998 A+ engine
Year:1986


i am looking for the standard hs4 carb setting please

all the best james

[Dan]

There isn't a standard setting, your carb is tuned for your engine. There is a setting called the initial position, from where the fine tuning is done. Search the forum for this, but it is in Haynes.

[BLUE ITALIAN JOB]

run engine to normal temp , back off tickover screw - make sure choke lever fast idle is clear , now turn on one and half turns ,
remove suction cover and piston , turn up the jet adjusting nut to bring the jet flush with the bridge of the carb , refit piston and cover ,
turn jet adjusting nut two full turns - 12 flats - ,
basic settings , tickover and mixture WILL need to be trimmed as ness ,
turn the jet adjusting nut in/up to weaken and down/out to richen the mixture ,
if the settings are near to correct you should be able to test with the piston lift pin ,
when lifted the rpm may increase slightly and you will be very near
" " " " increases considerably you have a rich mixture
" " " " immediately you have a weak mixture
lift the piston only by about .8 mm

[mk=john]

Model:myfair 998 A+ engine
Year:1986


i am looking for the standard hs4 carb setting please

all the best james

The Haynes SU manual is very good. the factory setting for the carb is around 12 flats open for the mixture, and 1.5 turns for the throttle idle screw from closed. This should get the car running so you can get some heat into the engine, but as already said, it has to be tuned for the car, as things like engine condition etc are taken into account.

Single carbs are easy to tune as explained..........can be a nightmare doing twin HS2's!