Remanufactured, Refurbished & Rebuilt
Gemini Pumping Unit Engines

G26P Natural Gas Pumping Unit

For 23 years we have offered remanufactured, refurbished and rebuilt Gemini pumping unit engines, or G26P natural gas pumping units. These 26hp two cylinder natural gas engine pumping unit are compact power units. We have power units, long blocks for exchange and a complete parts inventory to match them. Gemini Engines (Remanufactured) - We have been building these 26hp two cylinder natural gas engine pumping units and compressor engines for 23 years. Compact power units, long blocks for exchange, as well as complete parts inventory are available.


Continuous Duty:
Type: water-cooled, two cylinder horizontal opposed, natural gas power unit.
Engine Features:
Over 75,000 Gemini engines are powering pumping jacks in oilfields from the frozen tundra's of Canada, to the mountains of South America; from the deserts of the Middle East, to the jungles of Indonesia. Many of the original engines built in the 1940's are still running today. Tough means they work harder, longer.
Heavy one piece alloy iron with reinforcing ribs. Replaceable alloy iron cylinder liners surrounded by extra large water cooling passage.
Forged steel. Oversized journals for three main bearings. Counterweight balanced.
Forged steel with precision ground lobes.
Stellite faced valves and valve seat inserts.
Connecting Rods:
Forged steel, heavy section with drilled passages for lube oil to piston pin bushings. Replaceable precision insert type bearings.
Aluminum alloy. 4 rings. Top ring groove machined in nickel cast iron insert for long life. Full floating pin.
IMPCO Model 125. Dry trap air cleaner with replaceable element.
Mechanical, gear driven, pressure lubricated.
Altronic I, solid state, capacitive discharge. Permanently timed.
Heavy-duty 12-volt electric with power plug receptacle and start button.
High ambient pressurized radiator. Circulating pump. Dual thermostats. 17" fan and guard. Radiator core guard.
Gear type pump. Full flow spin-on lube oil filter. 18-quart capacity. Full block & head distribution.
Clutch and Drive Sheave:
Twin Disc CL111 clutch. 3-groove (combination B or C section) drive sheave (optional 6.3", 8.0" or 10.0' pitch diameter)

Optional Equipment

  • Exhaust muffler kit (includes two mufflers)
  • Shielded ignition system (Altronic I)
  • Sour gas radiator
  • 12‘ starter cables with power plug one end, clips other end
  • 12‘ starter cables with power plugs each end and one extra socket for mounting near 12V
  • Power supply
  • Special safety controls
  • Low-pressure gas regulator
  • Horizontal exhaust

Engine Specifications

Model G-26P Engine Specifications

Number of cylinders 2
Bore 4-3/8 in.
Stroke 4 in.
Displacement 12 cu. in./1.97 liters
Number of Cycles 4
Compression Ratio 10:1
Lubrication Full Pressure
Lube Oil Filter Spin-On Full Flow
Lube Oil Capacity 18 qts.
Cooling 7 psi Pressurized Radiator
Ambient Capability 130° F +
Coolant Capacity 22 qts.
Carburetor Type IMPCO 125 Down Draft
Air Filter Dry Type
Governor Pierce Mechanical
WR2 200 lb-ft2 Max.
Ignition Altronic I Capacitive Discharge
Exhaust Twin
Max Torque 77 lb. ft.
Starter 12-Volt Delco
Safety Switches Oil Press., Water Temp.
Flywheel Dia. 25”
Clutch Twin Disc CL111