cooling system is in a two circuit arrangement. The cooling  liquid is supplied by an integrated pump in the engine  through the cylinders and the cylinder head to the radiator.  The cooling system has to be installed, so that vapor coming  from the cylinders and the cylinder head can escape to the  top via a hose, either into the water tank of the radiator or  to an expansion chamber. The expansion tank is closed by a  pressure cap (with excess pressure valve and return valve).  As the temperature of the coolant rises, the excess pressure  valve opens, and the coolant flows via a hose at atmospheric  pressure to the transparent overflow bottle. When cooling  down, the coolant is sucked back into the cooling circuit. quantity in the oil tank must be checked before putting the  engine into service as the oil is consumed during operation  and needs to be replenished.  The 503 UL DCDI, 582 UL DCDI engine types are equipped  with a breakerless, single capacitor discharge ignition unit  with an integrated generator.  [Figure 11-5]  The 447 UL  SCDI engine is equipped with a breakerless, single capacitor  discharge ignition unit with integrated generator. The ignition  unit is completely free of maintenance and needs no external  power supply. Two charging coils fitted on the generator  stator, independent from each other, each feed one ignition  circuit. The energy supplied is stored in the ignition capacitor.  At the moment of ignition, the external triggers supply an  impulse to the control circuits and the ignition capacitors  are discharged via the primary winding of the ignition coil.  The secondary winding supplies the high voltage for the  ignition spark. Generally, the smaller two cycle engines are designed to run  on a mixture of gasoline and 2 percent oil that is premixed  in the fuel tank. The engines are planned to run on an oil- gasoline mixture of 1:50. Other engines use oil injection  systems that use an oil pump driven by the crankshaft via the  pump gear that feeds the engine with the correct amount of  fresh oil. The oil pump is a piston type pump with a metering  system. Diffuser jets in the intake inject pump supplied two- stroke oil with the exact proportioned quantity needed. The  oil quantity is defined by the engine rotations per minute and  the oil pump lever position. This lever is actuated via a cable  connected to the throttle cable. The oil comes to the pump  from an oil tank by gravity.  NOTE: In engines that use oil injection, the carburetors are  fed with pure gasoline (no oil/gasoline mixture). The oil  Due to higher lead content in aviation gas (AVGAS),  operation can cause wear and deposits in the combustion  chamber to increase. Therefore, AVGAS should only be  used if problems are encountered with vapor lock or if the  other fuel types are not available. Caution must be exercised  to use only fuel suitable for the relevant climatic conditions,  such as using winter fuel for summer operation.  Electric System Lubrication Systems Fuel System Oil Injection Lubrication of Rotax 503 UL DCDE,  582 UL DCDI, and 582 UL DCDI  LA LC1 LC2 Spark plug Spark plug Spark plug Spark plug K D C Electronic box 1 Electronic box 2 S H1 H2 C S H1 H2 D K GEN P1 Yellow P2 Gray Black/yellow Green Red/white White Black/yellow Green Red/white White Black/yellow Figure 11-5  Rotax 503 and 582 electrical system. 11-6