Monday, June 11, 2018

4 Barrel Carburetor Tuning

4 Barrel Carburetor Tuning

A little trick I came up with to reduce mess and make this easier. Instead of pulling the carburetor off the vehicle, I clamp the fuel line at the tank then run the engine till it dies due to lack of fuel. This will allow me to take the carburetor apart with a minimum amount of mess while keeping it installed on the engine.






Loosen up and disconnect steel fuel feed line from the carburetor


This Holley 600 takes a 5/16 socket to unbolt the fuel bowl. 


Use a shop towel to catch fuel if needed, but if you use my trick it should be very little if none at all.


Preventively put a show towel under to catch excessive fuel from the fuel bowl. Next carefully wiggle back and forth till bowl separates from the main body. 


This has a reusable gasket that is in good shape.


This carb came with #65 Jets and is running to rich. There are various sizes. Jump 2- 3 sizes when tuning.



After you swap jets reassemble the carburetor and begin tuning again. Don't forget to unclamp fuel line in back. I am stuck waiting on parts. Something you will find out soon is that hardly anyone knows how to tune a carburetor anymore. Another thing you will learn is that most parts stores don't carry basic tuning items like Jets, so you should order more than one set or your going to be stuck waiting for parts. My carb came with 65's but it was running way to rich, so I am waiting for a couple sets of Jets. 60's and 57's. This is only one step to tuning carburetor there are other things as well pending on how the throttle acts. You can change the Accelerator pump cams to control initial fuel dump and you can change vacuum secondary springs to increase or decrease speed that the secondary opens. 

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