I should also replace bushings... I dont know if its worth...
Do the Holley 4175 carbs comes to defects that I could find buying an used one that I have to take care (as the wrapped horn of the Qjey)?

 

On the Holley make sure none of the screws are stripped particularly the bowl screws. On the Quad, why dont you pull the airhorn off and make sure you set the float correctly and that the needle is correctly installed. I believe the measurement is .250.

 

Could you send me a picture with the screws marked so that when I go to see the carb I can check them? Thanks!

 

You can get a Holley spreadbore rebuild kit for less than $45

 

I believe he meant the screw holes... not the screws. The accelerator pump is the most common problem but I have had to repair the main body (bowl screw threads) as well. The accelerator pump is the small rectangular device under the carb fuel bowl with a lever attached to it... 4 screw holes. These get over-tightened because they frequently come loose. The fuel bowls attach to each end of the carb (front rear) with 4 screws each. The main body threads for these 8 screws sometimes strip... again usually due to over-tightening... but more often due to sour gas. All of the screws are supposed to be torqued with an inch-pound wrench... but very few people have an inch-pound wrench...so they use the built-in torque wrench in their arm... with and error rate of 50%... or more.

 

Many info thank you! Which book should I buy in order to understand all these things and also the torque of the screws? I have an inch-pound wrench...

 

Torque, inch pounds: -Thread- -Dry- -Lubricated- (-20%)
Fuel Bowls 12-24 25-30 20-24
Throttle Body to Main Body 12-24 30-50 24-40
Primary (Main) Jets 1/4-32 30-40 24-32
Power Valve, several small holes 1/2-28 40-50 32-40
Power Valve, two large holes 1/2-28 100 80
Discharge Nozzle (squirter) 48-52 38-42
Choke Cover 8-32 12 10
Secondary Metering Plate 8-32 12-18 10-14
Float Hinges etc 6-32 7-10 6-8
Carb Mounting 5/16-24 60-80 50-60
Fuel Inlet 9/16-24 175-200 140-160
Fuel Inlet 7/8-20 200-250 160-200
Accelerator Pump Cover 8-32 12-18 10-14
Note: Lubricated torque figures can be 10 to 25% lower than dry torque figures.
I pulled this info from an Excel spreadsheet so getting the columns to line up was a problem.

I'll let somebody else suggest a good Holley book. That's not my forte.

 

This carb should have a divorced choke, as the Qjet. Does it uses the same choke?