He' guys,
I have a question about tuning/checking with a holley 4165/4175 serie.
If i want to check or tune this holley with a vacuum-tester ......what's the way to do this?
:confused: And how to adjust this(which adjust-screws first?).

Thanks a lot!!!!! graemlins/thumbsup.gif
EDDY merlin.

I always tune by ear.

I tune by ear also. I belive if you want to use a vacuum gauge you would adjust the front mixture screws first. I belive you want to get the highest vacuum reading.

Eddy,
Beings your question was how to tune with a vacuum gauge, its kind of hard to do that with your ear!

Hook the vacuum gauge up so you are getting manifold vacuum, meaning don't use a port like for your vacuum advance. straight into the manifold if possible, or where your PCV goes into the carb.

If I remember correctly, the 4175, or might be the 4165 have a reverse idle adjustment, where it screws IN to make rich and OUT to lean, just oppsite of most Holleys.

But just turn your idle screws about 1/4 turn at a time until your vacuum starts to drop and then go the other direction until the highest vacuum reading can be achieved, then do the other side.

If you have a tach/dwell meter this helps also, your goal is to achieve the highest vacuum and rpm by adjusting your idle set screws.


Rocky

QJ replacement carbs
4165 is a DP & 4175 is a VS.
They are reverse idle.
The mix screws control air flow to the idle/cruise mix.
Not AF mix flow as normal holleys.
The DP's need big sec squirters if running lower # gears &/or small motors.

Thanks all of you!!!!!!!
I'm gonna check this out!!!!!!!

See ya later!!!! graemlins/thumbsup.gif


EDDY merlin.