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EC P7-MRK Pro Rebuild Kit for HR High Volume(Double Stack, Alky)Carburetors
P7-MRK EC Pro Mylar Double Stack HR Rebuild Kit
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EC P7-MRK Pro Rebuild Kit for HR High Volume(Double Stack, Alky)Carburetors

Part Number: P7-MRK
Online Price: $22.99
Phone Order Price:$25.99
You Save:$3.00(12%)
EC P7-MRK Pro Rebuild Kit for HR High Volume (Double Stack, Alky) Carburetors
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Description

EC P7-MRK Pro Rebuild Kit for HR High Volume (Double Stack, Alky) Carburetors


High-Performance Methanol Rebuild Kit for HR-Series Racing Carburetors

The EC P7-MRK Pro Rebuild Kit is built specifically for Tillotson HR-series high-volume (double-stack) carburetors used in methanol (alky) applications. Designed for serious racers, this complete kit includes premium upgrades, including our Fast Action diaphragm, BOPET fuel pump diaphragm, and all critical service parts—plus a detailed parts diagram to ensure accurate DIY reassembly.


Purpose-Built for Racing Professionals

Developed by EC Carburetors for the small engine racing community, our Pro Gasket Kits are engineered to outlast and outperform standard OEM and aftermarket alternatives. We prioritize durability under racing conditions, not cost-cutting margins.


Key Performance Features

Fast Action Main Diaphragm

Our exclusive high-performance metering diaphragm includes a “wagon wheel” style center with consistent dowel height for smoother fulcrum arm movement. This upgrade improves throttle response and fuel metering precision—ideal for race-tuned engines.


.093" Alky Inlet Seat (Short, Cross-Hole)

The kit includes a short seat with a .093” orifice, commonly used in methanol-fueled setups, reed or rotary valve 2-strokes, and high-displacement 4-stroke gas engines. While known as an “alky” seat, this part is versatile across fuel types and engine configurations.


Captured Needle and Fulcrum Arm Assembly

The captured-style fulcrum and needle improve reliability when the carburetor is mounted with the pump stack facing downward—keeping the arm and needle in constant, secure contact. 


BOPET (Mylar®) Fuel Pump Diaphragm

Unlike stock stock "snakeskin" Polytetrafluoroethylene (PTFE), our bi-axially oriented polyester film (BOPET) diaphragm offers superior resistance to methanol, ethanol, and other harsh fuels. It improves fuel delivery consistency and lasts longer in demanding race environments.


Exclusive Parts Diagram Included

Every EC Pro Kit includes a detailed parts diagram and component breakdown to help racers and builders properly identify, assemble, and service their carburetors. This level of documentation is not included in OEM or generic rebuild kits.


What's Included in the Kit:

  • Fast Action Main Diaphragm
  • Metering Diaphragm Gasket
  • BOPET (Mylar®) Fuel Pump Diaphragm
  • Fuel Pump Diaphragm Gasket
  • Inlet Valve Diaphragm
  • Inlet Valve Gasket
  • Brass Fuel Strainer Screen
  • Fuel Strainer Cork Gasket
  • .375" Welch Plug
  • .093" Inlet Seat w/ Cross Hole (0.538" Length)
  • Captured Inlet Needle
  • Captured Fulcrum Arm
  • Copper Inlet Seat Gasket
  • High/Low Side Needle O-Ring
  • 1.375" HR Flange Gasket


Compatibility

The EC P7-MRK fits all HR-series high volume (double stack) methanol-style carburetors, including:

  • HR-181B
  • HR-191G
  • And other HR-series race carburetors using a .093" inlet seat and captured needle setup.

Direct replacement for Tillotson RK-104HR, with upgraded and more complete components.

Rebuilding an HL-series carburetor? You'll need the EC P8-MRK Kit instead.


Recommended For:

  • 4-cycle methanol kart engines
  • 2-cycle reed or rotary valve methanol setups
  • Racers needing high-flow, double stack metering
  • Builders seeking race-grade durability and precision

FAQ

Q1: What carburetors are compatible with the EC P7-MRK Pro Rebuild Kit?
A1: The EC P7-MRK rebuild kit is designed for HR-series high volume (double stack) carburetors, including the HR-181B and HR-191G models. It fits any carburetor that uses a .093" inlet seat and a captured needle.


Q2: What is the difference between the P7-MRK and P8-MRK rebuild kits?
A2: The P7-MRK is specifically designed for HR-series carburetors, while the P8-MRK is for HL-series high-volume carburetors. The main difference lies in the flange gasket size and specific seat dimensions suited to each carburetor model.


Q3: Why is the BOPET (Mylar®) diaphragm better for methanol applications?
A3: The BOPET diaphragm is more fuel and chemical resistant than traditional PTFE diaphragms, making it ideal for methanol and alcohol applications. It also offers superior durability and fuel metering consistency, making it a superior option for racing engines.


Q4: What does "captured" mean when referring to the needle and fulcrum arm?
A4: A captured needle setup means that the fulcrum arm "captures" the dowel on the needle’s head, ensuring constant contact and better fuel metering. This setup is preferred when the carburetor is oriented with the fuel pump stack facing downward.


Q5: Can I use the EC P7-MRK kit on non-racing carburetors?
A5: The EC P7-MRK is engineered for racing applications with high-performance methanol engines. If you are looking for a standard rebuild kit for non-racing applications, we recommend the P7-RK kit, which is designed for more typical fuel and carburetor configurations.


Q6: Does this kit include a parts diagram for assembly?
A6: Yes! Every EC Pro rebuild kit comes with a detailed parts diagram that helps DIY racers properly identify parts, assemble their carburetor, and ensure it’s correctly reassembled. This is something no other OE or aftermarket kitsinclude.


Q7: What’s the difference between the EC P7-MRK and the EC P7-RK kits?
A7: The P7-MRK is specifically for HR-series methanol carburetors, while the P7-RK is a more general rebuild kit with fewer specialized components. If you’re working on a high-performance methanol engine, the P7-MRK is the better option due to its upgraded parts.


Q8: How do I know if I need this kit for my carburetor?
A8: If you're working with an HR high-volume (double stack) carburetor that uses a .093" inlet seat and captured needle (e.g., HR-181B or HR-191G), this is the correct rebuild kit. If you’re unsure, consult your carburetor model and specifications before purchasing.

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