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Aftermarket carb setup


OkieBronc

Member
Joined
Nov 12, 2024
Messages
24
City
United States
Vehicle Year
1985
Transmission
Automatic
Have a 1985 Bronco 2 2.8. Accuspark swapped, and I have a street avenger 350cfm.
The squirter jets seem to pump too much gas when I give it throttle and it wants to flood the engine. Anyway if tuning this out or changing it?
 
I'm not familiar with that carb...
But first try to shorten the stroke on the "squirters". Carbs I'm familiar with have holes in the arms that can be used to lengthen or shorten stroke.
 
I’ll check that out, thank you. I’m don’t know much about carbs yet this is the first one I’ve messed with. It seems to idle fine and go into gear fine. When I give it a good amount of throttle I believe the jets near the top push too much gas into it and it floods. Or when I come to a stop it wants to bog down and die. So maybe adjust the curb idle screw and mess with the idle mixture as well?
 
I've never had the need to tune a carb for anything more complicated than a single cylinder. Just found the manual. I know we have people with more carb skills. Hopefully they'll be along.
 
In your original post you were asking about the fuel accelerator pump adjustment. Your next post indicates a different problem.
I suspect you have too big of a carb. There are ways to tune around it but I'm not the one to help, I'm just good enough to fumble thru my own stuff...

But I will load a pic of the accelerator pump and arms. Pump circled in blue, arms circled in green.

Screenshot_20250427-100152.png
 
...I suspect you have too big of a carb...

I wondered that myself, when I saw that some of the applications are roughly 5.0L, but I know nothing about carbs on that size engine. It is listed as fitting a Ranger with the 2.8.

Edit: I've found 3 calculators that suggest 219CFM for that size engine at 85%VE. That seems to be a standard formula...
Edit2: That's actually the smaller smaller of 2 carbs on Holley's website for an 85 Ranger 2.8. The other is a 500CFM. Can't imagine needing that much even for forced induction...
 
Last edited:
Yeah, changing the jets and the power valve could help. But again, its over my teaching ability.
 
I hear ya there. I couldn't teach someone to do what I have on a small engine. Lots of plug chops, and tuning by ear/feel. Just trying not to blow it up along the way.
 
Play with throttle opening speed. If it has too much pump, opening the throttle really quick will help, if it doesnt have enough pump it will want you to try and open the throttle really slow. Sometime people dont know the difference between rich and lean.
350 holley isnt too big for your build, they run those 2.0l engine all the time. A 500 would work fine with enough accelerator pump, and the right power valve.
Is this carb new or used.
 
Play with throttle opening speed. If it has too much pump, opening the throttle really quick will help, if it doesnt have enough pump it will want you to try and open the throttle really slow. Sometime people dont know the difference between rich and lean.
350 holley isnt too big for your build, they run those 2.0l engine all the time. A 500 would work fine with enough accelerator pump, and the right power valve.
Is this carb new or used.

yes it is a new carb. Smells a bit rich like a sweet gas smell. I have a pressure gauge as well, what’s a good vacuum reading for the 2.8l if you know by chance? I’ll look at that today as well. I’ll do a little tweaking around with it and see. It seems to lean out too much after I give it throttle, but when I press the throttle too quickly it floods it. So it may be a combo of not enough gas at idle which would be idle mixture screws if I’m thinking correctly. And too much gas would when I press the throttle too far in may be because of the throttle speed. I’ll read through that link the other guy provided as well see if I can’t find a good happy medium
 
The factory carb would have 1.08 on the side of the bowl, that would flow approximately a 280 cfm, your 350 cfm should work OK. I suspect you'll need some smaller jets and it will involve some trial and error. You should be able to look up which jets it has in Holley's catalog for a starting point. I would get some bowl gaskets in case the factory still uses the original sticky paper ones. I would get some jets 2 to 4 numbers smaller to start, install them and road test it. Repeat as necessary until you like the way it works.
The accelerator pump cam can also be changed to a smaller one but try repositioning it first, the cams have 2 screw holes and the piece it attaches to usually has 3 holes.
If you have vacuum advance, attach the hose to the spark port on the passenger side of the carb.
 
so I believe I was having a choke and idle screw issue/timing was off a little. I got it running pretty good now, just having an issue now when I come to a stop after driving it’ll kill itself. Another issue I’m having is an oil leak, does the harmonic balancer from the 2.9l fit the 2.8l?
 

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