Holley 4175 carb
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Le Mans Master
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From: Loveland
Holley 4175 carb
What size accelerator pump discharge nozzle are you running?
And what is a,,, anti-pullover pump shooter, vs a regular holley squirter?
And what is a,,, anti-pullover pump shooter, vs a regular holley squirter?
Last edited by kodpkd; Sep 10, 2022 at 02:41 PM.
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From: At my Bar drinking and wrenching in Lafayette Colorado
Not knowing what list number 4175 you have, it's impossible to make a recommendation. Depending on list number, model 4175 Holleys came with # 25, 28, 31, 37, and 40 primary accel pump discharge nozzles. If you have a list number that used the 25 or 28 nozzles, bump it up to a 31 - the models that came with the #25 nozzles often have a tip-in bog. If you have a list number that came with 37 or 40 nozzles, I'd suggest looking at issues other than discharge nozzle size, such as accel pump arm action and setup, as suggested by Mel. Many newer Holley carbs have quality control problems with the accel pump cam follower lever not resting on the pump cam, but riding on the throttle shaft return spring. This will cause a tip-in bog from lack of movement of the lever when the throttle is moved.
Lars
Lars
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Le Mans Master
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From: Loveland
The acc pump is adjusted correctly. It is a 4175 0-80555-C, it currently has a size 40 anti pullover shooter. It has the 30 cc acc pump.
I assumed the 40 was big enough. If anything maybe to big. I didn't know how 5000 ft elevation might change things.
It's an L79 350 HP
I assumed the 40 was big enough. If anything maybe to big. I didn't know how 5000 ft elevation might change things.
It's an L79 350 HP
Last edited by kodpkd; Sep 11, 2022 at 11:30 AM.
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Thread Starter
Le Mans Master
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From: Loveland
Thank you. Yes. I do think it's interesting the number of techniques I see online, how to adjust the acc pump. There are two adjustments that need to be correct. One closed throttle and one full open throttle. Closed throttle there shouldn't be any play between the throttle bar and the pump lever. This insures zero delay between throttle movement and the fuel shot. Full throttle you need to be sure the acc pump isn't bottomed out. They always push a feeler gauge between the bar and the acc lever at WOT. If the spring compresses when doing this, the bar is probably bottomed out. You need to be sure the acc lever moves and not just the spring.
Edit:
I have also found there is a little slack in the throttle bar and the acc pump bar. You can adjust the spring bolt so there isn't any gap between the two but the acc pump isn't being activated until later in throttle movement. You need to take up this slack, so as soon as the throttle moves there is a squirt of gas.
Edit:
I have also found there is a little slack in the throttle bar and the acc pump bar. You can adjust the spring bolt so there isn't any gap between the two but the acc pump isn't being activated until later in throttle movement. You need to take up this slack, so as soon as the throttle moves there is a squirt of gas.
Last edited by kodpkd; Sep 12, 2022 at 02:17 PM.
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