Relationship between idle jets and idle mix screws |
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Relationship between idle jets and idle mix screws |
era vulgaris |
May 9 2016, 04:06 PM
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#1
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J is for Genius Group: Members Posts: 982 Joined: 10-November 13 From: Raleigh, NC Member No.: 16,629 Region Association: South East States |
How much can one compensate for the other?
For example, with larger jets and idle screws further in, could you tune a set of carbs identically to another set of the same carbs that had smaller jets with the mix screw further out? I want to experiment with going a little leaner at idle and seeing how my engine likes it. I'm trying to decide if I should order a smaller set of idle jets or if I can achieve the same result by just turning the screws in further. Basically, what is the difference? Don't they achieve the same ends? Obviously there's a limit on the rich side because there's only so much fuel a jet will allow to flow. But if you're trying to lean it out, what's the difference between going to a smaller jet or just turning in the screw? |
era vulgaris |
May 10 2016, 09:37 PM
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#2
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J is for Genius Group: Members Posts: 982 Joined: 10-November 13 From: Raleigh, NC Member No.: 16,629 Region Association: South East States |
Sorry, the missed thread comment was directed at Justinp71, as he mentioned ignition, vacuum leak, etc. I should have made that clearer, just didn't feel like cutting and pasting quotes.
I wouldn't necessarily say that it runs good cold and not when hot. I don't really start driving until it's warmed up. But even so, it usually runs great. It's only occasionally at a stop that this happens. Most of the time when I come to a stop the idle is strong and stable. It's just the few times when it isn't, that's annoying. I'll have to check into that stuff. FWIW, my distributor is a 5 year old Mallory Unilite. I don't think it would be that dirty, but it's worth a check. Are they known to have problems with sticking advance plates? I know the stock dizzys can have that happen, as it happened to the one on my old car. My pushrods are chromoly, so valve adjustment is zero anyway. I have the swivel foot adjusters. When I adjust them, I get them tight enough so the rocker arm doesn't move, but loose enough that the foot can still spin. Checking them hot reeeeally doesn't sound like fun! But sounds like it's worth it. I did a hot compression test a few weeks ago. All cylinders were within a couple psi of 140. If I had a stuck open valve, wouldn't I get a large reduction in compression in one cylinder? Sounds like a lot of fun on that 356! I've definitely been in that position in the audio world! (IMG:style_emoticons/default/beerchug.gif) I did go for a long drive this evening, and felt the carbs and manifolds when I got back. They manifolds were warm, but definitely not uncomfortable to hold my hand against. The carbs were even less warm. Fuel pump is in the front of the car, btw. |
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