For visually impaired users: Browse the streamlined version of our website.

O.S. FS155-A P Ring 70R F6020

Note: Manufacturer does not allow using discount coupons
Low Price: $499.99
Add To Cart Add to Wish List
In Stock Online!
Usually ships in 24 hours
FREE Shipping Eligible!
This item is eligible for Super Saver Shipping Learn More
This is an O.S FS155-A Alpha Series 1.55 4-Stroke Pumped Engine. 200-size power in a 120-size package!

How do you get 200-size power from a 120-size engine? O.S. calls it the FS155-a. Since the FS155-a is a pumped 4-stroke, you’ll enjoy 2.6 hp at all times, regardless of tank position, attitude or fuel level. Its novel re-circulation system bathes working parts in constant lubrication, for less friction and wear!


  • Ideal for 120 size scale and sport models and aerobatic models requiring stable power and linear throttle response
  • PD-08 pump and 70R carburetor integrated with regulator ensures stable fuel delivery regardless of model attitude and fuel level
  • F-6020 three piece design muffler with center heatsink
  • Redesigned internal lubricating system eliminates breather tubing from the
  • crankcase
Displacement: 1.548 cu in (25.36cc)
Bore: 1.323" (33.6mm)
Stroke: 1.126" (28.6mm)
Practical RPM: 2,000 - 10,000 RPM
Power Output: 2.6 PS, 2.56 HP @ 10,000 RPM
Engine Weight: 28.40 oz (805g)
Muffler Weight: 3.35oz (95g)
Carburetor Settings:
Needle Valve: 2-1/2 - 3 turns from fully closed
Mixture Control Valve: Factory set, make only small adjustments if
needed, after adjusting needle valve as described in manual, turn
30° to lean idle mixture or 90° counterclockwise to richen mixture
then back again 45° clockwise
Width at Mounting Tabs: 2.6" 67mm)
Crankcase Width below Mounting Tabs: 1.8" (47mm)
Length from Drive Washer to rear of Carburetor: 5" (127.5mm)
Height from Mounting Tab to Pushrod Cover: 4.5" (114mm)
Height from bottom of Crankcase to Pushrod Cover: 5.4" (138.6mm)
Distance between Mounting Hole Centers Same Side: 0.98" (25mm)
Distance between Mounting Hole Centers Opposite Side: 2.3" (58mm)
Distance/front Mounting Hole Center to Drive Washer: 2.5" (64.5mm)
Distance/ Center of Engine to Drive Washer: 3.03" (77mm)
Crankshaft Size: 5/16-24

  • FS155-a P Four Cycle Engine with PD-08 Pump System, 70R Carburetor
  • F-6020 Muffler, Header Pipe, type F Glow Plug, Needle Valve
  • Extension Cable, Instruction Manual
Needed to Complete:
  • Fuel: Glow fuel with 5-20% nitro content and no less than 18% lubricant content
  • Propeller: 16x8-12 or 17x8-12
  • Glow Starter
  • Field equipment

This product was added to our catalog on July 29, 2019