RPMLegends18
Well-Known Member
You put too big of jets in it? Or is there too big of jets?
What happens if....
- Thread starter RPMLegends18
- Start date
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ramcharger
Dismember
It runs like crap and barfs large quantities of black smoke.
demon seed
The Original Demon Seed
And don't forget the fouled plugs and runs like crap (opps Ramcharger said that).
Terry
Terry
RPMLegends18
Well-Known Member
so when you put bigger jets in does the carb need to be leaned down?
ramcharger
Dismember
Sounds like we need to start from beggining. What kind of carb are we talking about here?
Larger jets supply more fuel, smaller jets supply less. Air bleeds have the opposite effect. Larger bleeds will lean the mixture out and smaller bleeds will richen it up. Each has an effect in a different place in the fuel curve. Then there are power valves if we are talking about Holleys.
There's no point in supplying an engine with more fuel than it needs or just jetting up for sake of it. On the the other hand, running lean can destroy an engine. An experienced builder or tuner can jet just by reading the plugs and by the seat of the pants. There are meters out there that can tell you what A/F ratio you're running but they are not cheap. Not the good ones anyway.
So, lets start from the beggining and find out what you have and what you're trying to do. Don't leave anything out. We need everything to try to help you accomplish your goals.
Larger jets supply more fuel, smaller jets supply less. Air bleeds have the opposite effect. Larger bleeds will lean the mixture out and smaller bleeds will richen it up. Each has an effect in a different place in the fuel curve. Then there are power valves if we are talking about Holleys.
There's no point in supplying an engine with more fuel than it needs or just jetting up for sake of it. On the the other hand, running lean can destroy an engine. An experienced builder or tuner can jet just by reading the plugs and by the seat of the pants. There are meters out there that can tell you what A/F ratio you're running but they are not cheap. Not the good ones anyway.
So, lets start from the beggining and find out what you have and what you're trying to do. Don't leave anything out. We need everything to try to help you accomplish your goals.
Dustr-70
Active Member
Ramcharger had a great explanation of the basics you need to know. I'd like to add on thing. When you ask if you need to lean down the carb if using bigger jets I am thinking maybe you are referring to leaning the mixture down with the idle mixture screws.
If that's the case understand that those are idle mixture screws. They are in the idle circuit and really aren't going to affect you off idle.
RPMLegends18
Well-Known Member
sorry guys i have been out of town, but i will get the number off the carb. its a holley spread bore vacuum secondary P.O.S. it was just some OEM replacement carb we had in the box and i needed a carb
lead69
hopeless car junkie
If its the zinc/top plate style its a pos imo and i would junk it-but the older spread bore holleys can run very well and get decent fuel mileage.
RPMLegends18
Well-Known Member
this thing is oooollldddd its got a gold looking color. well heres the problem. when i first put it on the new engine it would idle but as soon as i put it in gear and put a load on it it would start running like crap, so my dad told me to put bigger jets in it and i did. that made it run pretty good just cruising around. now if i try to get on it and it gets around 3500-4000 RPMs it just starts doing the same sputtering crap.. its really annoying cause I know the car would run better than this. So I was wondering if i put even bigger jets in would that help the problem or is that even the problem? Its using the stock electronic ignition box and an OEM replacement coil. The intake is a edelbrock performer series. And the carb is...List 7006-2 2016 Those are the numbers on the choke housing? I think thats what its called. I did take it all apart and clean it all. With a new rebuild kit. So it has a new power valve, new gaskets, new everything. But it still runs like a POS. What am I doing wrong here? I am not really too excited about putting a double pumper on there, I do have to drive this thing everyday. And here is some more info if this helps. It is the stock distributer it has been rebuilt new pick up coil with the air gap set to the proper .004 I believe it was I cant remember exactly with the brass feeler gauge. New cap (its tan color real heavy piece, my dad said that its a really good cap) new rotor, 8MM plug wires (nothing performance there...just plug wires) and Bosch Platinum Spark Plugs. Exhaust is...Summit brand headers, 2 1/2" to flowmasters then turndowns before the rear end housing. the exhaust passages that flow from the head through the intake (im assuming to warm the carb) have been blocked off...umm am I not really sure what the timing is set at, my dad did that.
I hope this is enough info to help...
I hope this is enough info to help...
ramcharger
Dismember
What size jets are you running now? Also, make sure you don't have any vacuum leaks and all unused vacuum ports are plugged.
RPMLegends18
Well-Known Member
I put 78's in it. All the plugs are on it...how do i check for a vacuum leak?
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