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Adjusting Holley carb.

6K views 4 replies 4 participants last post by  DansEdgli 
#1 ·
I have a holley 465 avenger model on my xflow in the XF and for some reason it is revving at 1500. I can get the revs to 800 when i use the clutch to stay stationary but when when the clutch goes in the revs rise to 1500 again.
It also tries to run on after ive turned it off for around 15 seconds. Then it floods itself.
My question is how can i adjust the carb? its only new so i dont which screws to turn.
Is the problem my carby or something else?
Also sometimes when i brake hard the car will stall especially on Hot days, is this a carb problem or is it my fuel pump? How can i fix that? I have a holley Blue fuel pump and regulator but havent had time to get it put in yet.

Thanks Guys
Dan.
 
#3 ·
There is an idle adjustment screw on the left hand side of the carb (throttle linkage side). Mine also used to run on when the idle was high, if its carboning up this can also cause run on, but I reakon lowing the idle should stop the problem.

The stalling under brakes etc. also happened to me and was caused by fuel level in fuel bowl being too high. Adjust the needle & seat to adjust this. To do this, you will notice a screw & nut on the top of each fuel bowl. Lossen the nut to allow you to turn the adjustment screw. Then remove the site plug on the fuel bowl on the right hand side of the carby. With the engine idling at running temperature adjust the fuel level with the adjustment screw until the bowl level is level with the bottom of the site plug hole. If fuel is just trickling out slowley this is OK. You will need to do this on both fuel bowls. Replace the site plugs and tighten the locking nut on each adjustemt screw.

This can be a bit of a messy job, especially if the fuel level is real high and fuel pisses out all over the place. Or if like mine (I susspect yours also) it rocks a bit at idle because of the cam.

I hope this all makes sense, but if you remove the air cleaner and take a look you will find the idle adjustment, neddle & seat adjustment and the fuel bowl site plugs.
 
#4 ·
All the above post is correct...but you dont necessarily need the car on to adjust the needle and seat. Its prolly safer to do it with the car off. As for tuning the Holley there will also be 1 thin screw EITHER SIDE of the holley. These are the air and fuel mixture screws. BASIC rule of thumb is screw them all the way in until just tight, then turn each screw back about 1-1/2 turns. This may vary with jetting changes. This will also prevent some run on. If tho u get sick of the run on, as u turn the car off take your foot off the clutch in second gear gradually, and the car should stop comfortably as if you have used the clutch to stall the car normally. Its a bit of a trick but works well when u have mastered it. I had to do it in my V8 XF all the time no matter what I did to the carb.

ViGiLaNtE
 
#5 ·
Sweet! thanks for the info guys, now i know what to do.
I found a vacuum hose was off and this lowered the revs back to 1000 and stopped a bit of the running on.
I need a stronger spring as well i think because the throttle linkage doesnt come all the way back to rest against the adjustment screw.
Ill adjust the float bowls today. And youre right mine does rock from side to side due to the cam.

Thanks Again.
Dan
 
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