The Fuel Pump of the Arctic Cat 047-838 snowmobile must respond to the specific needs of its two-cylinder two-stroke engine. The factory original requirement is 25-30 L/h (pressure range of 15-20 kPa) fuel flow rate. The fuel pump’s installation hole distance from the flange is 72.5±0.2mm (to SAE J1828 standard). According to the 2022 Arctic Cat Technical Announcement, the fuel system of this model is matched with the AC-0470838-FP (part number). Its built-in ceramic bearing can withstand the motor speed of 4500±150 RPM in a condition between -40℃ and 80℃, such that the fuel flow in low-temperature start-up is not less than 85% of the nominal value. Third-party test findings indicate that while using the alternative Walbro WR-284-10-1 model (flow rate 28 L/h±5%), when voltage drops below 12.5V (the original factory requirement is 13.5V±5%), the fuel pressure will fall from 18 kPa to 9 kPa. This causes a maximum engine power loss of up to 23% under high-altitude (> 3,000 meters) operational conditions.
Checking for compatibility is ensuring attention to physical parameters. Original Fuel Pump’s filter screen density is 80 mesh (0.18mm), while that of typical models such as Mikuni BN40-32 is only 60 mesh (0.25mm), and the impurity passing rate increases by 3.2 times. The possibility of clogging of carburetor is enhanced by 47% (as per the 2021 statistical survey of 200 malfunctioning devices conducted by Alaska Snowmobile Association). The installation size deviation should be controlled within ±0.3mm. For instance, if the third-party pump body height is 1.5mm higher than the original factory standard (92.5mm), it will strike the bottom plate of the oil tank and generate resonance noise above 75dB (ISO 362-1 standard limit is 70dB).
In the performance enhancement plan, the HF-SnoPro 280 fuel pump of HighFlow Racing (35 L/h±3% flow rate) can improve fuel supply stability by up to 18%. The high-pressure fuel pipe (the inner diameter is increased from 5mm to 6.5mm) needs to be replaced simultaneously; otherwise, turbulence will be triggered when the fuel flow rate exceeds 4.2m/s. The pressure fluctuation range was expanded from ±5% to ±12%. The field test conducted by consumers in Quebec, Canada in 2023 reported that after installing the HF-SnoPro 280, the engine cold starting time at -30℃ was shortened from 12 seconds to 7 seconds, but rose the fuel consumption rate by 8% (from 1.8L/hour to 1.95L/hour).
The cost comparison is as follows: OEM Fuel Pump (240-280 cost) lifespan is 800 hours (about 5 winters), while the third-party compatible components such as Winderosa FP-0470 (160-190 cost) lifespan is 500 hours. Maintenance cost, however, needs to be added to additional filter replacement cost (15 for each 100 hours). According to figures presented by the Montana Snowmobile Club, the overall average cost of repair due to the improper installation of incompatible fuel pumps is 650, which includes carburetor cleaning (120), spark plug replacement (40), and rescue costs ($490).
Concerning the compliance risk, Part 1051 of the 40 CFR of the United States Environmental Protection Agency (EPA) stipulates that if the modification of the Fuel Pump causes the exhaust hydrocarbon (HC) emissions to be more than 4.5g/kWh (the original factory design value is 3.8g/kWh), a penalty of $3,750 per device will be incurred. In the 2022 Minnesota case, a modifier was ordered to recall 83 units and was penalized $310,000 for using uncertified HighFlow fuel pumps, which led to HC emissions over the standard to 5.2g/kWh. Priority must be attached to the procurement of the Fuel Pump kit certified by ARCTIC Cat (e.g., AC-0470838-FP-C), whose EMC anti-interference property based on the ISO 11452-2 standard ensures that the error rate of the fuel pump control signal is less than or equal to 0.3% within a medium where the power density of electromagnetic radiation is 100V/m.