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003 Inlet Tension Pop-Off Spring
003 Inlet Tension Pop-Off Spring
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003 Inlet Tension Pop-Off Spring

Part Number: 003
Online Price: $2.00
003 Inlet Tension Pop-Off Spring | Carburetor Fuel Flow & Pop-Off Pressure Control
Availability: In Stock.

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Description

003 Inlet Tension Pop-Off Spring for Diaphragm Carburetors


The 003 Inlet Tension Pop-Off Spring is a precision-calibrated component used to control pop-off pressure in diaphragm-style carburetors. It plays a key role in regulating the rate at which fuel flows into the high and low side circuits of the carburetor—especially during low-speed operation, idle, and throttle transitions.

Pop-off pressure refers to the pressure required to open the carburetor’s inlet needle valve. This pressure is controlled by the spring’s tension and installation height, and is a vital factor in fine-tuning fuel delivery for small engine performance.


It’s important to note that pop-off pressure is not the same as fuel pressure. Most fuel pumps in small engine applications only deliver around 1 PSI. A pop-off pressure rating of 10 PSI, for example, does not indicate that the system must generate 10 PSI of fuel pressure—it simply reflects the force needed to overcome the spring and unseat the needle valve.


The 003 spring provides a specific pressure profile ideal for engines requiring softer needle actuation and increased fuel flow responsiveness at lower RPMs.


Key Features:

  • Regulates pop-off pressure in diaphragm carburetors
  • Enables precise fuel delivery at low engine speeds
  • Optimized for consistent needle valve operation
  • Compatible with many Tillotson, Walbro, and similar carburetor models
  • Ideal for tuning or rebuilding 2-stroke and small engine carburetors

FAQ

Q1: What does the 003 Inlet Tension Pop-Off Spring do?
A1: It regulates the pop-off pressure in diaphragm carburetors by determining when the needle valve opens to allow fuel into the metering chamber—critical for precise low-speed operation.


Q2: Is pop-off pressure the same as fuel pressure?
A2: No. Pop-off pressure is the amount of force required to open the carburetor’s needle valve, determined by the spring’s tension. Fuel pressure, delivered by the pump, is usually only about 1 PSI.


Q3: What carburetors are compatible with the 003 spring?
A3: The 003 spring is compatible with many diaphragm-style carburetors used in small 2-stroke engines, including models from Tillotson, Walbro, and similar manufacturers.


Q4: How do I tune pop-off pressure with the 003 spring?
A4: Pop-off pressure is adjusted by the spring’s tension and installation height. A pop-off pressure tester is recommended for accurate tuning.


Q5: When should I use the 003 spring over others?
A5: The 003 spring is ideal for applications needing quicker needle valve response and slightly lower pop-off resistance—useful in low-speed tuning and responsive throttle setups.

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