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HS6 Carb Question

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Ray Smith

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My Hayes manual indicates that to enrichen the mixture on the BJ7 carbs you rotate the jet adjuster in an anticlock wise i.e. upward direction. It would appear to me that rotating the jet adjuster in an anticlock wise direction would be going in a downward direction.

Would someone please clarify. I thought that an upward direction would cause the mixture to weaken, and a downward direction would cause the mixture to enrich.

Thanks,

Ray
 
Ray, as far as I know the BJ7 has the HS6 carbs. Though my car is originally a BJ7 as well, PO installed HD8 carbs. On these carbs rotating the screw cw means enrichening the mixture.

Lowering the jet enrichens the mixture, bringing the jet up to a higher position weakens it.
 
Different screws entirely on the HS6 carb Vs the HD8's,Rick . However, lowering the jet as you indicated does richen the mixture while raising it leans the HS6 Carbs out---Keoke
 
Rick and Keoke,

To summarize: Rotating the jet adjusting nut counter clock wise will make the mixture richer, whereas, rotating the jet adjuster clockwise will lean out the mixture.

Ray
 
Hullo Ray.I too had a problem with this.What you are doing,of course, when changing the mixture is moving a tapered (conical)pin ,vertically into a staionary tapered (conical) hole.The more the pin is in the hole the smaller is the resulting orifice for the fuel to pass thro.i.e less fuel and a weaker mixture.When I adjust my H6 carbs can never remember which way to turn! So I hold a bolt with a nut on it vertically to represent the male screw and the adjusting nut on the carb..Then I wind the nut up to weaken ,down to richen. Repeat this motion on the adjusting nut and all is well.I have found that a one or two flat (on the nut) can make a big difference.
 
Well John, I think in this case the "PIN"{ Needle} is stationary and the "hole" {JET} is moving up and down vertically as the adjusting nut is turned.---Keoke /ubbthreads/images/graemlins/yesnod.gif
 
You turn the nut cw or ccw depending on whether you are viewing the nut from above or below. Turning the nut ccw as viewed from above the nut, will move the jet up & lean the mixture. If you are looking up at the end of the nut from below, reverse directions & turn it cw to move the jet up & lean the mixture. What are we going to do when all clocks are digital?
D
 
Yeah Dave I know that, it is just less confusing to reference the movement of the Jet up or down.Kinda like the near side far side issue when talking to the Europeans depends on whether they are left hand or right hand drive cars and I just didn't know which end the book was looking at---Keoke /ubbthreads/images/graemlins/laugh.gif
 
Funny that this comes up today. My HJ8 had post-ignition problems after my last tune-up. So yesterday, I tried adjusting the mix to lean it out some. Still ran after I shut it off. I'm turning the screw clockwise a half turn at a time. Am I doing this right? I've yet to fix the problem, but giving my stellar mechanical skills, I'm luck the carb didn't fall out of the car.
 
SHG
Under the vacuum chamber there is a small pin. With the engine running lift the pin on each carb individually - the engine should speed up momentarilly the drop off to an almost stall speed. Adjust THAT carb - if it runs higher coninually - too rich [lower jet], if it stumbles - too lean - lower jet. Then move to the other carb. It also helps to a] do an ignition tune up first, and b] have a Unisin air flow meter to balance the air flow. I do this with the air cleaners off then after reinstalling them do a final twique.

Regards, Bob
 
HI SHG, sounds like you were going in the wrong direction with the mixture screw. When the mixture screw is turned "CW" you are richening the mixture. Turning it "CCW" leans it out. Be sure that the Idle speed is not too high it should not be more than 1000 RPM on the car Tach with the engine at its normal operating temperature. Most of the Tachs run about 200 RPM high so that is about right. However, Run on in the BJ8 is common, most of us ignore it and use third gear to stop the engine at shut down. Additionally, be sure the choke cables are set up correctly---Fwiw---Keoke
 
Moving the ligting pin only a little. It will have the ability to move a lot but that wont tell you anything. This pin raises the piston to let more air in but too much will stall it regardless of the fuel mixture. I've learned this through trial and error. On the BJ8 that front carb pin is difficult to get at (like no room) but with practice and the little finger in that tight place you can get good results.
 
/ubbthreads/images/graemlins/nonono.gif /ubbthreads/images/graemlins/nonod.gif NO TH. RFThom, is correct. Lifting the pin disables that carburetor so you can assess the richnes or leaness of the carburetor that the engine is running on and make the correct tuning adjustment. For example if you lift the pin 1/32" and the engine almost dies ,stumbles, you are too lean.If it speeds up and does not drop back to smooth runing, continues to speed up, you are too rich.To get at the front carb pin make up a "little" spoon like tool that will cradle the pin and lift it.---Keoke---P.S. If you have one of those little paint can openers,you know with the little claw on the end and an oblong handle, just put a slight bend in the shaft and it will let you lift the front pin.
 
I wasn't disagreeing with RFThom. Just trying to insure that the pin not be push all the way up but as you said only a 1/32". I like the idea of the paint can opener.
 
OH OK TH, I see what you were saying my bad. Glad you liked the Cheap pin lifter.---Keoke /ubbthreads/images/graemlins/laugh.gif
 
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