12 replies to this topic

[lawn bowls]

i just brought a remanufacted holley 600 double pumper square bore for my turbo holden 6 what are the factory primary and secondary jets as it has a slight stumble from idle until 2000 rpm then it clears it self up.havent adjusted nothing on the carby except the idle.

[ozyozyozy]

Jets dont cause that, either acclerator pump or incorrect power valve.

[lawn bowls]

thanks mate i brought the carby from humes performance do they have a good reputation on carbys?

[Lima31]

A carby is only as good as the tuner, not the person you bought it off ... did they just supply it or tune it?

[lawn bowls]

the factory jets in the primarys are 66 i should try 63.i have a 600 vac secondary that was on the car and had 63 primary jets and didnt have the stumble under 2000 rpm.

[ozyozyozy]

Its tricky, coz its on a turbo, may require different things to conventional.
Stumble all the way to 2000, should be well off the idle circuit by then.
PV are for power enrichment aswell, if they dont open till late incorrect vacuum rating they can cause this aswell.
I agree that it is a lean spot.
Changing jets adjusts overall fuel.
depending the type of carb you can change the air bleeds to adjust the transition from idle to main fuel circuits and fuel at points in rpm.
I would reccomend going to an experienced carb tuner.
im no expert at all with them, just what i hve been learning, been playing with some of this stuff only this week with my own as have made a carb change.

[lawn bowls]

its a 4776-3 carby and below that number is 2429 so what does this mean?

both vacuum ports on the primary and secondarys have been blocked off

[lawn bowls]

the primary nozzle are 28 and the secondary nozzle are 32 power valve is 6.5 

[lawn bowls]

draw through

[lawn bowls]

maybe i should go blow through turbo it will be more effefient