Carbuerator tuning
Senior User
Joined: Nov 2000
Posts: 187
Likes: 0
From: Santa Cruz
Carbuerator tuning
When it comes to carbs my skills is at the bare minimum. I just rebuilt a 4160 series Holley 4 barrel (1850-3). And am going to plant it on my 302 tommorrow. I was just wondering if anyone has tips on tuning these up to spec, living in california I could use as much extra mileage as I can pinch out of this thing. The carb isn't exactly level in the engine bay, so would it be better to set the float level with the truck on an incline so the carb is level, or set it when the truck itself is at it's regular driving angle? Also, is there a sure fire way to set the secondary float level since it's vaccuum operated? Any help would be appreciated, and any extra tips besides what I'm asking about (idle screws?)would be a god send. Thanks
Craig
Craig
Elder User
Joined: Mar 2001
Posts: 898
Likes: 0
From: SF Bay area
Carbuerator tuning
Hi Craig, I would adjust your carb at normal driving level and see what happens. Your instructions should tell you how to set the float levels on both bowls. there is a screw on the side of the carb for each bowl, so when you see fuel comin out of the holes, the level is too high. start you initial idle mixture adjustment at 1 1/2 to 2 turns out. good luck.
Wayne
e-mail
http://home.pacbell.net/whomrig
Wayne
http://home.pacbell.net/whomrig
Moderator
Joined: Jan 2001
Posts: 56,979
Likes: 2,734
From: Virginia
Carbuerator tuning
Your carb choice is good for your 302. I've had several of these carbs on 302's and out of the box on a stock 302 they run very well with no tuning changes. I usually set my float levels with the vehicle level and the sight plug open with a rag below to catch the fuel. I set it so no fuel comes out of the hole unless I shake the vehicle a little by the front fender. Setting the secondary fuel level is the same as for the front. It may be a little slower to react if you try to lower the fuel level, but if you have the secondary butterfly stop set per factory specs, the secondaries do use fuel at idle and the fuel bowel level will eventually drop down. As far as setting the mixture screws, I turn one side in until the engine starts running rough and then back it out until it runs smooth. Go around and do the same thing for the other side and then do both sides again. On the last go round I back the screw out till it runs smooth, and then back the screw out 1/4 turn more.
Senior User
Joined: Nov 2000
Posts: 187
Likes: 0
From: Santa Cruz
Carbuerator tuning
Thanks for all the help guys, I appreciate it. I put the carb on and it ran fine for my roadtrip halfway down california. Then a backfire blew the power valve and things got worse from there. Looks like I'm rebuildin it again. But thanks again
Craig
Craig
Thread
Thread Starter
Forum
Replies
Last Post
