Chainsaw design has seen incremental improvements over the decades, but every few generations, a piece of equipment comes along that fundamentally changes how we cut wood. For years, heavy-duty commercial saws relied entirely on traditional carburetors to meter fuel into two-stroke engines. The arrival of a true fuel injected chainsaw changed the landscape permanently, stripping away delicate needles, chokes, and carb adjustments in favor of raw digital performance and split-second throttle response.

Quick answer: A fuel injected chainsaw replaces the traditional mechanical carburetor with an electronic fuel injection (EFI) system, delivering computer-optimized fuel metering directly into the crankcase. The Stihl MS 500i is the first commercially available saw with this technology, offering an incredible power-to-weight ratio of 1.24 kg/kW, instantaneous acceleration from idle to full power in 0.25 seconds, and zero manual carburetor tuning regardless of altitude or ambient temperature.

What Is a Fuel Injected Chainsaw and How Does EFI Work?

To appreciate what makes the Stihl MS 500i stand out, it helps to understand how standard two-stroke engines operate versus an electronic fuel injection (EFI) design. Standard professional saws use a diaphragm carburetor where engine vacuum draws fuel through small metering jets. While reliable, carburetors struggle with changing barometric pressures, drastic temperature swings, and sudden throttle changes. Operators often have to adjust High and Low jet screws on the jobsite or settle for suboptimal air-fuel ratios that reduce torque and run hotter than necessary.
In a fuel injected chainsaw, the carburetor, choke lever, and high/low adjustment screws are completely removed. Instead, an internal generator powers an Electronic Control Unit (ECU) alongside fuel injection components. Sensors continuously measure pressure inside the crankcase and monitor ambient temperatures. The microchip calculates the exact volume of fuel needed for optimum combustion, firing an injector pump that delivers atomized 50:1 premix gas directly into the crankcase several times per millisecond. The practical advantage in the woods is immediate. Without a choke valve obstructing airflow through the intake tract, the engine draws air far more efficiently. Cold starts require no complex starting procedures: simply push the primer bulb, pull the starter cord, and pull the trigger. The system self-calibrates immediately, ensuring maximum engine torque under heavy load whether you are felling timber at sea level or bucking logs high up in alpine mountain passes.

STIHL MS 500i Specifications and Engine Power Breakdown

The Stihl MS 500i was built from the ground up to maximize the benefits of electronic fuel injection. Pushing a massive 79.2 cc engine displacement while weighing only 13.9 lbs (6.2 kg) for the powerhead alone, it delivers a class-leading power output of 6.7 horsepower (5.0 kW). This ratio allows loggers and tree care professionals to carry the physical footprint of a standard 70cc class saw while pulling the heavy cutting capacity of an 80cc or 90cc timber saw.
Region Average Price Notes
USA $1,499 – $1,699 Includes standard 25” bar option
UK £1,250 – £1,400 Varies by retailer
Australia AUD $2,200 – $2,600 Includes bar and chain
India ₹125,000 – ₹145,000 Import-dependent pricing
Matching the right guide bar and chain pitch to this saw is critical for getting the best performance out of the EFI system. The MS 500i thrives with guide bars ranging from 20 inches up to 36 inches in length, utilizing standard 3/8" pitch chain with a .050" or .063" gauge. When paired with a 28-inch STIHL Rollomatic E Light bar, the unit balances naturally in the hands, significantly reducing operator fatigue during long days of felling, limbing, and bucking heavy hardwood.
Specification Parameter STIHL MS 500i Values husqvarna 572 xp (Carb/AutoTune)
Engine Displacement 79.2 cc (4.83 cu. in.) 70.6 cc (4.31 cu. in.)
Power Output 6.7 bhp (5.0 kW) 5.8 bhp (4.3 kW)
Powerhead Weight (Dry) 13.9 lbs (6.2 kg) 14.5 lbs (6.6 kg)
Fuel System Type Electronic Fuel Injection (EFI) Carburetor with AutoTune
Power-to-Weight Ratio 1.24 kg/kW 1.53 kg/kW
Recommended Bar Lengths 20" to 36" (50 to 90 cm) 18" to 28" (45 to 70 cm)
When considering investments in high-end forestry machinery, understanding total equipment cost is vital. The MSRP for the STIHL MS 500i generally ranges between $1,450 and $1,750 depending on your choice of bar length, chain setup, and local dealer pricing. While the price point sits higher than traditional carbureted saws like the STIHL MS 462 or MS 661, the speed gains and fuel savings quickly offset the initial cost for professional users.

Real-World Cutting Performance and Handling Characteristics

On an active jobsite, the defining characteristic of this saw is throttle response. Conventional saws take a split second to spool up from idle to wide-open throttle as fuel flows through the carburetor circuits. The MS 500i accelerates from 0 to 62 mph (100 km/h) chain speed in just 0.25 seconds. This lightning-fast acceleration transforms limbing work, letting you flick through branches with minimal trigger delay and maximum precision.
Specification Detail
Engine Type 2-Stroke, Electronic Fuel Injection (EFI)
Displacement 79.2 cc
Power Output 6.7 HP (5.0 kW)
Weight (Powerhead) 13.9 lbs (6.3 kg)
Bar Length Options 20” – 36”
Fuel Tank Capacity 0.785 L
Chain Oil Capacity 0.325 L
Chain Pitch 3/8”
STIHL 500i Chain Speed Up to 26.3 m/s (86 ft/s)

Pro tip: Because the MS 500i reaches maximum chain speed almost instantly, operator technique must adapt. When entering a heavy pull cut on a 30-inch oak trunk, establish your cutting stance before touching the trigger. The sudden torque curve can catch unseasoned operators off guard if the drive spikes are not firmly engaged into the bark, increasing the potential risk of kickback if proper stance and proper PPE are neglected.

Beyond raw speed, the saw maintains high torque sustained under thick wood load. The internal computer reads engine rpm drops under heavy force and adjusts injection timing on the fly, preventing engine bogs where traditional saws might stall out. If you regularly manage large timber clears, learn more about gear selection in our comprehensive guide to professional chainsaws to pair your powerhead with the right bar length for your specific cutting environment.

STIHL 500i Problems, Maintenance, and Husqvarna Comparisons

Despite its advanced engineering, no power equipment is immune to issues on the job. Understanding common operator complaints and maintenance quirks helps keep this saw running reliably year after year. Most reported problems stem from fuel contamination or minor misunderstandings about electronic component care rather than mechanical defects.
  • Engine Hard Starting or Hydro-Locking: Flooding can occasionally occur if the manual purge bulb is pumped excessively while the saw is already warm, or if the starter rope is pulled half-heartedly. Pulling the cord firmly without touching the throttle trigger clears the chamber smoothly.
  • Fuel Filter Sensitivity: EFI systems operate under high fuel pressure via precise micro-nozzles. Dirt or moisture in the tank will foul the system quickly. Using fresh 50:1 ethanol-free fuel mixed with high-grade synthetic oil like stihl hp ultra is mandatory.
  • Air Filter Dust Buildup: Because the MS 500i pulls immense volumes of air to match its rapid engine cycle, fine dust can build up around the HD2 air filter quickly. Clean the filter element regularly with warm soapy water or compressed air blowing from the inside out.
  • Diagnostic Requirements: Unlike standard saws where a screwdriver fixes idle speeds, ECU or sensor fault codes require a dealer diagnostic connection (STIHL MDG1 tester) to reset software parameters if an electronic module fails.
Model Engine Type Power Price (Approx.)
STIHL MS 400 C-M Carbureted 66.8 cc / 5.4 HP $1,099
STIHL MS 462 C-M Carbureted 72.2 cc / 6.0 HP $1,299
STIHL MS 500i Fuel Injected 79.2 cc / 6.7 HP $1,499
STIHL MS 661 C-M Carbureted 91.1 cc / 7.2 HP $1,599
A common question among loggers is whether competitor options exist: Does Husqvarna make a fuel injected chainsaw? While Husqvarna has experimented with EFI technology in high-capacity cut-off saws, they have chosen to refine auto-adjusting carbureted systems like AutoTune for their main chainsaw lineup (such as the husqvarna 572 xp and 592 XP). These saws use digital chips to manage needle jetting automatically, but they still rely on traditional carburetor venturi physics rather than direct electronic fuel injectors. Proper maintenance also involves choosing the correct chain profile. Deepen your understanding of drive link gauges and cutting teeth by reading our complete analysis on chainsaw chains to maximize cutting efficiency across different wood species.

Is the Fuel Injected STIHL MS 500i Right for You?

Deciding to purchase the MS 500i comes down to your cutting volume, physical demands, and budget. For timber fallers, arborist crews, land clearers, and serious landowners processing cords of heavy firewood every season, the MS 500i offers an unmatchable balance of light weight and massive cutting power. The reduced physical strain over a full day of work makes a noticeable difference in body fatigue and safety. However, casual home users cutting fallen branches a few times a year will rarely tap into the full capabilities of an electronic fuel injection system. In those instances, intermediate farm-and-ranch models or mid-range professional units remain more economical choices. To explore smaller alternatives that still deliver reliable power, check our guide on STIHL chainsaws for a complete breakdown of carbureted options. If you decide to step up to the MS 500i, ensure you purchase directly from an authorized STIHL servicing dealer. Always outfit yourself with full Personal Protective Equipment (PPE)—including wrap-around chainsaw chaps, high-impact helmet systems with ear protection and face shields, cut-resistant boots, and heavy leather gloves—before pulling the cord on this fast-cutting piece of machinery.

Frequently Asked Questions

Does the STIHL MS 500i have a choke?

No, the STIHL MS 500i does not have a traditional choke lever or cold-start choke setting. Because the engine utilizes Electronic Fuel Injection (EFI), the system automatically calculates ambient temperature and air density to meter the exact fuel required for a cold start instantly.

What gas-to-oil ratio does a STIHL fuel injected chainsaw require?

The STIHL MS 500i requires a standard 50:1 fuel-to-oil mixture, combining 89 octane or higher mid-grade gasoline (preferably ethanol-free) with high-performance 2-stroke engine oil such as STIHL HP Ultra Synthetic.

How does the weight of the MS 500i compare to other professional saws?

The powerhead of the MS 500i weighs approximately 13.9 lbs (6.2 kg). This gives it a power-to-weight ratio superior to almost all saws in the 70cc to 80cc class, delivering 80cc power outputs at a weight comparable to traditional 60cc or 70cc powerheads.

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