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EC P8-MRK Pro Rebuild Kit for HL High Volume(Double Stack, Alky)Carburetors
P8-MRK EC Pro Mylar Double Stack HL Rebuild Kit
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EC P8-MRK Pro Rebuild Kit for HL High Volume(Double Stack, Alky)Carburetors

Part Number: P8-MRK
Online Price: $21.99
EC P8-MRK Pro Rebuild Kit for HL High Volume Alky Carburetors
Availability: In Stock.

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Description

EC P8-MRK Pro Rebuild Kit for HL High Volume (Double Stack, Alky) Carburetors


Professional-Grade Methanol Rebuild Kit for HL-Series Racing Carburetors

The EC P8-MRK Pro Rebuild Kit is designed specifically for high volume (double stack, methanol/alky) Tillotson-style HL carburetors. Built for the demands of high-performance karting and small engine racing, this kit includes upgraded components that deliver superior fuel compatibility, durability, and throttle response—everything you need for a complete and competitive rebuild.


Built for Racers, by Racers

Unlike standard OE or generic aftermarket kits, EC Pro Gasket Kits are constructed with racing conditions in mind. We use OEM-grade or better components—not to cut costs, but to maximize durability and performance under demanding track conditions.


Key Features & Performance Advantages


Fast Action Main Diaphragm

A proprietary performance upgrade from EC Carburetors, this high-response diaphragm features a “wagon wheel” center for consistent dowel height and smoother, more predictable fulcrum arm operation. This leads to quicker fuel meteringand better engine response under throttle.


Uncaptured Fulcrum Arm & Needle Setup

This kit includes an uncaptured needle and forked fulcrum arm, ideal for carburetors with upward-facing pump stacks or setups that experience frequent vibration. Our custom brass fulcrum arm is factory-set to .065" height, the optimal setting for most methanol (alky) applications. We still recommend verifying the setting before installation.


.093" Short Alky Inlet Seat with Cross-Hole

Commonly used in methanol-powered engines, rotary valve and reed-valve 2-stroke engines, and larger 4-cycle racing engines. Though called "alky seats," the .093” orifice is also suitable for high-performance gas applications with increased flow needs.


High-Performance BOPET (Mylar®) Pump Diaphragm

This kit includes a bi-axially oriented polyester film (BOPET) pump diaphragm—known for exceptional fuel and chemical resistance. This Mylar® diaphragm significantly outperforms traditional PTFE “snakeskin” diaphragms in methanol applications. It’s our top recommendation for 4-cycle alky engines and 2-cycle reed valve racers.


Exclusive Assembly Diagram Included

No guessing, no confusion. Every EC Pro Kit comes with a detailed parts breakdown and diagram—something you won’t find in OEM or generic aftermarket kits. This allows for confident, DIY reassembly without the risk of costly mistakes.


Kit Contents:

  • Fast Action Main Diaphragm
  • Diaphragm Gasket
  • BOPET (Mylar®) Fuel Pump Diaphragm
  • Fuel Pump Diaphragm Gasket
  • Inlet Valve Diaphragm
  • Inlet Valve Diaphragm Gasket
  • Brass Fuel Strainer Screen
  • Fuel Strainer Cork Gasket
  • .375" Welch Plug
  • .093" Inlet Seat with Cross Hole (0.538" length)
  • Uncaptured Inlet Needle
  • Uncaptured Brass Fulcrum Arm (preset to .065")
  • Copper Inlet Seat Gasket
  • High/Low Side Needle O-Ring
  • 1.00" Flange Gasket
  • 1.060" Flange Gasket
  • 1.125" Flange Gasket


Compatibility:

The EC P8-MRK Pro Kit is designed for HL-Series High Volume (Double Stack, Alky) Tillotson-style carburetors, including:

  • HL-314G
  • HL-248A through HL-248E
  • HL-355A through HL-355E
  • HL-360B, HL-360C
  • HL-368A
  • HL-380A, HL-380B
  • HL-304WXA

Direct replacement for Tillotson RK-104HL rebuild kit


Why Choose EC P8-MRK Pro?

  • Premium aftermarket upgrades made specifically for methanol racing
  • More complete and reliable than OE and budget kits
  • Ideal for DIY racers and engine builders who want race-day readiness
  • Backed by EC Racing’s experience in high-performance small engine development

FAQ

1. What carburetors are compatible with the EC P8-MRK Kit?

This kit fits HL-series high volume (double stack, alky) carburetors, including:

  • HL-314G
  • HL-248A–E
  • HL-355A–E
  • HL-360B, HL-360C
  • HL-368A
  • HL-380A, HL-380B
  • HL-304WXA
    If your carburetor uses a .093" seat and uncaptured needle, this kit is likely compatible.


2. What does “high volume” or “double stack” mean?

“High volume” or “double stack” refers to the fuel pump stack design found on specific HL-series Tillotson-style carburetors. These stacks provide increased fuel flow, especially important in methanol-fueled racing engines.


3. What is the advantage of the BOPET (Mylar®) diaphragm?

The BOPET diaphragm in this kit offers:

  • Greater fuel and chemical resistance
  • Improved durability in methanol (alky) applications
  • Longer lifespan vs. traditional PTFE “snakeskin” diaphragms
  • Better pulse response for consistent fuel delivery


4. What’s the difference between captured and uncaptured needles?

An uncaptured needle is not held in place by the fulcrum arm. Instead, the arm rests on top of the needle. This setup is preferred when the carburetor is mounted with the pump stack upward, or for engines that operate in rougher track conditions, offering more stable fuel delivery.


5. Why is the fulcrum arm made of brass and pre-set to .065"?

The included brass fulcrum arm is preset to the optimal height (.065") for alky setups, ensuring consistent needle contact and metering. Brass provides added strength and precision. Always verify your height during installation in case of handling during shipping.


6. What OEM rebuild kit does this replace?

The EC P8-MRK Pro Kit is a performance replacement for the Tillotson RK-104HL rebuild kit, offering additional components, improved materials, and racer-focused enhancements.


7. Does this kit work for HR-series carburetors?

No. This kit is specific to HL-series double stack carburetors. For HR-series high volume (alky) carbs, use the EC P7-RK or EC P7-MRK kits instead.


8. Does this kit include an installation diagram?

Yes! Every EC Pro Kit comes with a full carburetor assembly diagram and parts breakdown — a must-have for racers and DIY builders to ensure correct installation.

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