What does an accelerator pump on a carb do?
An accelerator pump is a component on a carburetor. The accelerator pump is responsible for providing the momentary additional fuel needed under heavy acceleration conditions. When the pedal is suddenly pressed, the throttle will suddenly open, immediately adding additional air for additional power.
What happens if main jet is too big?
For example, using too large of a main jet will cause more fuel to enter the combustion chamber than it can efficiently burn. This will result in a “sputter” at full throttle. It could best be described as a rapid misfire.
What is the symptoms of bad accelerator pump?
Signs that your accelerator pump may need to be replaced include:
- Car does not accelerate smoothly when gas pedal is pressed hard (note: a bad accelerator pump does not affect slow acceleration, only fast acceleration)
- Engine stalls or stutters during hard acceleration.
- Exhaust smoke.
What does the leak jet do on a FCR carb?
The leak jet effectively reduces the fuel pumped to the motor to a fraction of it’s potential, which helps prevent flooding and allows more consistent jetting. Without a leak jet, the pump will flow up to 3 seconds in duration.
What size pilot jet should I use?
The pilot jet is sized correctly if the fuel screw setting falls between 2.5-3 turns out. The pilot jet is sized correctly if the air screw setting falls between 1-2 turns out, with 1.5 being the sweet spot.
What happens if you bottom out the accelerator pump?
Bottoming out an accelerator pump diaphragm can lead to a damage over time, or even rupture the diaphragm itself, which can cause a fuel leak, and the associated headaches which come along with that. The first step is to adjust the accelerator pump actuation arm and the pump’s lever.
What does the accelerator pump do on a Holley?
In this quick video, Tom Kise of Holley goes over how to properly adjust the accelerator pump system on one of the company’s carburetors. As the name implies, the accelerator pump provides additional fuel upon acceleration of the engine, while the primary circuit catches up to demand.
What are the systems of the HSR carburetor?
The HSR carburetor is divided into four interdependent systems: 1. Choke system 2. Idle system 3. Main system 4. Accelerator pump system Each of these systems has its major effects in a different throttle range.
Why does the accelerator pump need to be tuned?
As the name implies, the accelerator pump provides additional fuel upon acceleration of the engine, while the primary circuit catches up to demand. As such, a poorly tuned accelerator pump circuit can lead to laggy off-idle performance.