Firman Tri-Fuel Generator Muffler Exhaust Adapter – 3/4" NPT Male

🇺🇸 PROUDLY MADE IN THE USA | AR-EXHAUST

Exhaust Adapter for Firman Tri-Fuel Generators

Upgrade your generator's exhaust outlet connection with this USA-made exhaust flange adapter, designed to attach directly to the existing muffler outlet of compatible Firman Tri-Fuel portable generators.

This adapter features a 304 stainless steel 3/4" NPT male threaded connection welded to a heavy-duty 1/4" mild steel mounting flange, providing a threaded connection for compatible exhaust piping, pipe unions, elbows, and other fittings.

It is particularly useful for customers building their own generator exhaust extension or custom exhaust outlet configuration while retaining the generator's original muffler.

IMPORTANT: This adapter attaches to the outlet of the original muffler, NOT directly to the engine's exhaust port.

Compatible Firman Generator Models

Customer-Confirmed Installation

Firman T08072 Tri-Fuel Generator

A customer successfully installed this adapter on his Firman T08072 generator using M5 mounting bolts.

He then connected his own separately purchased piping and fittings to create a customized exhaust outlet configuration.

The customer-provided installation photo included in this listing demonstrates the adapter mounted directly to the original generator muffler.

Additional Firman Models with Matching OEM Muffler Assembly

The following models are documented with the same Firman muffler assembly part number, 375413004:

• Firman T07573
• Firman T08071
• Firman T07571
• Firman T07571F

Because these generators share the same listed muffler assembly, they are expected to have the same exhaust outlet mounting configuration.

However, the adapter has not been physically tested by us on every model listed above.

Please verify your generator's muffler outlet configuration and compare the measurements in our product photos before ordering.

Other Generator Applications

This adapter may also work with other generator brands and models that have a similar two-bolt muffler outlet.

The mounting hole spacing must match our adapter, but mounting dimensions alone do not guarantee compatibility.

Other generators may use different mounting bolt sizes or thread pitches.

Always verify the original muffler outlet dimensions and mounting hardware requirements before purchasing.

Product Specifications

Important Information About 3/4" NPT Threads

The designation 3/4" NPT refers to a standard nominal tapered pipe thread size.

It does not mean the actual outside diameter of the threaded connection is exactly 3/4".

This adapter is intended for use with compatible standard 3/4" NPT female pipe fittings.

Please verify your intended fitting before ordering.

What's Included With Your Order

Each adapter kit includes:

• 1 Exhaust Flange Adapter with 3/4" NPT Male Thread
• 1 Exhaust Gasket
• 2 Stainless Steel M5 Socket Head Mounting Bolts
• 2 Stainless Steel Washers

The adapter is supplied with the components shown in our main product photograph.

NOT INCLUDED: Exhaust extension pipes, pipe elbows, pipe unions, couplings, flexible exhaust tubing, additional fittings, or any other components used to build a custom exhaust system.

Real Customer Installation – Firman T08072

One of our customers shared photographs of this adapter installed directly onto the original muffler outlet of his Firman T08072 Tri-Fuel generator.

The installation demonstrates how the adapter provides a threaded outlet connection that can be used with separately sourced exhaust piping.

How the Customer Installed It

1. He identified the two mounting holes at the original generator muffler outlet.
2. He installed the exhaust flange adapter using M5 mounting bolts.
3. He connected his own compatible pipe fittings to the adapter's 3/4" NPT male threaded outlet.
4. He used additional piping to create his desired exhaust outlet configuration.

The customer reported using M5 x 16 mm mounting bolts for his installation. He also mentioned that M5 x 20 mm bolts appeared suitable, although his confirmed installation used the 16 mm length.

The original Firman muffler hardware is listed as M5 x 14 mm in the applicable parts documentation.

The installation photograph is provided for reference only. All additional pipes and fittings shown in that photograph were supplied by the customer and are not included with this adapter kit.

Important Information About Mounting Bolts

This adapter includes M5 stainless steel mounting bolts and washers.

These are intended for the listed Firman muffler application.

If you plan to use this adapter on another generator brand or model, please be aware:

Even if the muffler mounting holes measure exactly 1.50" center to center, the original generator may use a different bolt diameter or thread pitch.

The included M5 mounting bolts may not fit those applications.

Before ordering, check:

• Mounting hole spacing: 1.50" center to center
• Original muffler outlet configuration
• Mounting bolt diameter and thread pitch
• Clearance around the muffler outlet
• Available space for additional exhaust fittings

Matching mounting hole spacing does not automatically guarantee compatibility.

Premium Materials and USA Manufacturing

This adapter is manufactured by AR-EXHAUST in the United States.

304 Stainless Steel Threaded Connection

The 3/4" NPT male threaded connection is manufactured from 304 stainless steel.

Stainless steel provides good corrosion resistance and durability for demanding exhaust applications.

Heavy-Duty Mild Steel Flange

The mounting flange is manufactured from 1/4" thick mild steel and welded to the stainless steel threaded connection.

The mild steel flange is not stainless steel and may develop surface oxidation during normal use.

Stainless Steel Mounting Hardware

Stainless steel mounting bolts and washers are included with the adapter kit.

The combination of welded construction, quality materials, and USA manufacturing makes this a practical connection component for compatible generator muffler applications.

Custom Generator Exhaust Applications

This adapter can provide a connection point for customers designing their own exhaust outlet configurations.

Potential applications include:

• Custom generator exhaust outlet piping
• Generator muffler outlet extensions
• Threaded exhaust connections
• Connecting compatible 3/4" NPT pipe fittings
• Custom exhaust routing where adequate clearance and proper support are available

This product is an exhaust connection adapter only. It is not a muffler, noise-reduction device, or complete exhaust extension system.

The original generator muffler remains responsible for noise reduction.

This adapter does not guarantee reduced exhaust noise or improved generator performance.

Installation and Safety Considerations

Generator exhaust systems operate at high temperatures and are exposed to engine vibration.

Any piping or fittings connected to this adapter must be appropriately sized, securely supported, and installed with sufficient clearance from combustible materials and other generator components.

Heavy or unsupported exhaust extensions can place excessive stress on the muffler, flange, and mounting bolts.

Modifying the original exhaust outlet may affect exhaust backpressure, engine performance, emissions compliance, or the manufacturer's warranty.

Do not remove or disable a required spark arrestor or emissions-control component.

CARBON MONOXIDE WARNING: Never operate a generator indoors, inside a garage, or in any enclosed or partially enclosed space, even when using an exhaust extension. Generator exhaust contains carbon monoxide, which can cause serious injury or death.

Follow the generator manufacturer's installation, operating, and safety requirements.

Please Review All Product Photos

Our photographs show:

• The actual exhaust adapter and included components
• Overall adapter dimensions
• 1.50" mounting hole spacing
• 1/4" mounting flange thickness
• 3/4" NPT threaded connection
• A customer-provided installation example on a Firman T08072 generator

Please compare these dimensions with your generator before purchasing.

AR-EXHAUST

PROUDLY MADE IN THE USA 🇺🇸

Precision-fabricated exhaust components for generators, small engines, and custom applications.