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So after reuilding my 351m and converting it to a 400, lets just say ive had alot of break in bugs. I finally got it running right other then a high idle. So long story short, after everything im having trouble with what i think is the carb. For starters the secondies are leaking. Its and electric choke holley 4160 600cfm. But what its going is ill go down the road and slow down or come to a stop it acts like it wants to die. It bogs down below idle then picks back up. What could that be? Does it need a rebuild ??
If it's what I remember you have to have it running...then remove a sight plug...then you need a box end on the nut on top all the while a giant flat head screwdriver in the slot....I can't remember if you hold the screwdriver and turn the nut or vice versa.... do it just untill the fuel starts slightly dribbling out of the sight plug hole.
If it's what I remember you have to have it running...then remove a sight plug...then you need a box end on the nut on top all the while a giant flat head screwdriver in the slot....I can't remember if you hold the screwdriver and turn the nut or vice versa.... do it just untill the fuel starts slightly dribbling out of the sight plug hole.
I think the screw is the jam and the nut adjusts the float.
Dave - - - -
This thread has me wondering how to tune the idle mix on a standard transmission vehicle...with the automatics we would creep up to a nice big tree and keep it in drive up against the tree while we adjusted the idle mix screws and speed....
So remove sight plug, which is on pass. Side i believe but what nut are yall talking about ?
There should be a nut & screw on the top of the carb around where the fuel line goes in.
Take a picture of the top of carb so we can point you to it.
Originally Posted by 82_F100_300Six
This thread has me wondering how to tune the idle mix on a standard transmission vehicle...with the automatics we would creep up to a nice big tree and keep it in drive up against the tree while we adjusted the idle mix screws and speed....
Idle mix is adjusted the same no matter what trany or carb you have.
If a v1 carb like on a 300 six motor you will have only 1 mix screw.
If a v2 or v4 carb like on most v8 motors you will have 2 mix screws.
Some v4 carbs may have 4 corner idle mix screws but they are fancy carbs.
After setting the timing & idle speed you set the mix screw(s) adjust each one the same amount to get the best idle. You may have to re-adjust the idle speed.
Dave ----
So remove sight plug, which is on pass. Side i believe but what nut are yall talking about ?
Here's a picture. You should have two, one front and one rear. You should set the rear one low, and then go out on the road and open up the secondaries a few times to lower the level in the rear. They dribble just a tiny amount of fuel through the lower holes in the secondaries to keep the fuel fresh back there. If you try to lower the level and let the truck idle, it will take forever for it to use the fuel up. It's better for it to be too low and then raise it up to the bottom of the site plug.
Here's a picture. You should have two, one front and one rear. You should set the rear one low, and then go out on the road and open up the secondaries a few times to lower the level in the rear. They dribble just a tiny amount of fuel through the lower holes in the secondaries to keep the fuel fresh back there. If you try to lower the level and let the truck idle, it will take forever for it to use the fuel up. It's better for it to be too low and then raise it up to the bottom of the site plug.
Franklin2, some of the new holley 600's I have seen lately do not have the external float adjustment. You have to pull the bowl and set the float by bending it and measuring it to spec's. It may just have something sticking in the needle and it may need to be cleaned and check the float level if it isn't adjustable from the outside like the older one's were. Or he could put a good 600 edelbrock on it......