Carter YFA, which way idle mixture works?
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Joined: Jul 2005
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From: Black Hills South Dakota
Carter YFA, which way idle mixture works?
I'm new at carbs and usually just get into trouble messing with them. My first rebuild attempt seemed to go pretty well, but it still seems to run rich and belch black smoke.
Had my first test rides with the newly rebuilt Carter YFA bolted to a 300-I6. There is only one mixture screw. Does turning it inwards lean the mixture? I'm still seeing black smoke at low speeds and at startup, even though the idle mixture screw is only half a turn out instead of 2.5 turns. So, maybe I'm going the wrong way to lean it?
I lowered the float a fair amount earlier, before installing the kit. It looks pretty close right now. As I understand the carb kit instructions, the spring should not be compressed at all when measuring float level. So, with air horn upsidedown, I lifted the float till it just touched the tip of the float valve and measured from there. I'd presume this to be a fairly critical adjustment, or is there a fudge factor? Would this cause the rich-running, or should I look at the main jet, which wasn't included in this kit?
Thanks!!
-Ed
Had my first test rides with the newly rebuilt Carter YFA bolted to a 300-I6. There is only one mixture screw. Does turning it inwards lean the mixture? I'm still seeing black smoke at low speeds and at startup, even though the idle mixture screw is only half a turn out instead of 2.5 turns. So, maybe I'm going the wrong way to lean it?
I lowered the float a fair amount earlier, before installing the kit. It looks pretty close right now. As I understand the carb kit instructions, the spring should not be compressed at all when measuring float level. So, with air horn upsidedown, I lifted the float till it just touched the tip of the float valve and measured from there. I'd presume this to be a fairly critical adjustment, or is there a fudge factor? Would this cause the rich-running, or should I look at the main jet, which wasn't included in this kit?
Thanks!!
-Ed
Senior User
Joined: Feb 2005
Posts: 185
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From: South Dakota
When i did my carb rebuild and had it installed i had the mixture screw out and had the truck running, then i turned the screw inward, closing it off then i turned about 2 to 3 times out till the engine ran smooth. When i tune a carb i do it by listening to the engine and smelling the exhaust fume's from the tailpipes. When its running rich it will blow black smoke.
Thread Starter
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Senior User
Joined: Jul 2005
Posts: 258
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From: Black Hills South Dakota
After some messing around, I think I've got it pretty close. For sure better than it was! It also has computer issues, but I think for now at least the carb is set. Thanks!
-Ed
-Ed
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