GT55 Gasoline Engine 54.9cc/3.

It's similar in appearance to other O.S. 2-cycle engines, with a large number of extra-deep and -thin cooling fins on the crankcase and head. A unique 1-piece crankcase design eliminates gaskets and enhances strength and precision.

Another major performance benefit is the IG-01 Capacitive Discharge Ignition. Developed from proprietary O.S. technology, it uses a microcomputer programmed for optimum spark advance. Magnetic sensors on the crankcase and prop drive detect ignition timing. The IG-01 also detects and compensates for wet plugs, ensuring quick starts. Designed to accept a wide range of input voltages, the IG-01 requires minimal current in standby mode and features a low-voltage warning (intermittent engine operation).

Features
Produces 20-30% more power than any other engine in its class
IG-01 Capacitive Discharge Ignition uses a microcomputer programmed for optimum spark advance through the use of magnetic sensors on the crankcase and prop drive, the IG-01 also detects and compensates for wet plugs to ensure consistent quick starts, also requires minimum current in stand-by mode and features a low voltage warning (intermittent engine operation)
Front mounted WLA-2 carburetor stays cooler for less heat
percolation and more consistent performance, simple and direct
throttle and choke linkages
Unique one-piece crankcase eliminates gaskets and enhances strength and precision
Front induction rotary valve crankshaft design for positive opening and closing of valve for optimum timing, no oil seal required which eliminates RPM loss due to additional friction
Massive front and rear crankshaft bearings for longer life and
maximum power output
Thin high-performance piston ring and high-strength aluminum alloy piston for reduced break-in and high compression from the very first run
Two year limited warranty through manufacturer beginning at date of purchase


Specs
Displacement: 3.352 cu in (54.93 cc)
Bore: 1.62 in (41.2 mm)
Stroke: 1.62 in (41.2 mm)
Output: 5.5 hp @ 7,000 rpm
Practical rpm: 1,500-8,000
Engine weight: 55.3 oz (1,580 g)
Igniter weight: 4.94 oz (140 g)

Requires
Propeller: 22x8 for break-in
22x10, 23x8, 23x10, 24x8, 24x10 for sport/acro/scale use
Two-Cycle Oil: Break-In, Klotz Modelube recommended, mix at 30:1 gas/oil mixture for 10 flights, 1.3 - 1.6 gallons (5-6 liters) of gas
After Break-In: mix at 50:1 ratio, See COMMENTS below
Muffler: See COMMENTS below
Fuel: Unleaded regular gasoline (no need to use high octane)

Comments
If using a different brand of oil other than Klotz, OS recommends their own mix ratio which may differ from the manufacturers' For 40:1, and 50:1 oils, OS recommends a 30:1 gas/oil mixture

25:1 is 5oz of pre-mixed 2-cycle oil or 151 ml per gallon of fuel
30:1 is 4.3oz of pre-mixed 2-cycle oil or 126 ml per gallon of fuel
40:1 is 3.2oz of pre-mix 2-cycle oil or 95 ml per gallon of fuel
50:1 is 2.6oz of pre-mix 2-cycle oil or 76 mll per gallon of fuel

The following mufflers are ideal for different applications;
J'TEC Large Wraparound Pitts Muffler, for inverted
mounting applications.
Bisson Wraparound, and Inverted mufflers will
also fit.
Slimline offers the following, #2125 Inverted Pitts Muffler, #2156 Side Canister, and #2155S w/Smoke
System.