holley carb balance

Is there a simple way of balancing up either side a holley carb. I had to adjust mine at the sva test to get the emissions into the uk reccomended levels . Since then I have noted that the exhausts on one side of the inlet feed are red hot while the other side of the outlets are cooler so I must have one side to lean to the other. ( the in let manifold supplies much the same way the bundle of snakes removes the exhaust )

Any one got a simple way of tuneing the mixture screws to balance the mix without the use of analysis tools

If I had a gas analyser I could test the out put through each exhaust until they were the same and this would ensure either side the carb is balanced. Havent got one 1
 
Both idle mixture screws in the primary metering block should be turned out the same amount. Around .75 to 1.5 turns from full in ( dont overtighten when checking!) If there is no noticeable change when adjusting you have one of the following or a blocked idle circuit.

Since you seem to have an excessive lean condition on one half of the carb, also check that you are sourcing brake booster & or PCV vacuum from a port or supply that is common to both sides of the manifold plenum or carb base rather than just one runner of the manifold. Also that you have no air leaks at any fittings etc.
 
HUW:
Holleys are actually very easy to tune and work on compared to Webers or similar. Assuming that none of the internal jetting was changed to achieve emissions compliance, the first thing to look for as JAC MAC advised is an air leak causing a lean condition. If you are using an older carb it may have some "foreign" (USA??) :)material in one of the internal passages or in an emulsion tube within the metering block. On a newer carb, it was mentioned on another post with pictures, illustrating the plating was peeling off inside the float bowls and on the metering blocks. It was a real ugly thing. Idle mixture screws usually end up about 3/4 of a turn open. Be sure the Mixture screws have a very small rubber or cork "O" ring sealing them within the metering block. Once adjusted properly they hold their tune forever and require very little attention. Spray a little carb cleaner in the 8 small brass air bleeds at the top of the ventuis to clear any dirt.

Rick
 
as you said really simple . running really well now with no over run or difference in exhaust temp. seemed best at one full turn on each needle
 
Gentlemen:

While we're on the subject of adjusting Holley carbs, has anyone tried the adjust-a-jets - they used to be made by Holley but now a company called PERCY’S makes ADJUST-A-JET METERING BLOCKS.

I'm having trouble getting my carburetor right - I'm now running a 670 Street Avenger after trying several other carbs, but it still needs some fine tuning. They adjust-a-jets allow you to adjust the jets externally with a needle valve rather than removing the metering blocks and the bowls - a messy operation!

John
 
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