If you are going to start this engine
by hand, definately start on one cylinder only. Once it fires you can flip the decompressor lever to bring the 2nd cylinder on line. The reason that this engine is so hard to start manually is because it has a very light flywheel. The old Volvo
diesels had a very heavy flywheel and you used the hand crank to get the speed up before flipping the decompressor lever. The inertia of the heavy flywheel then helped turn the engine past TDC and its firing point. With the light Yanmar
flywheel you have to make the effort and be very careful. If you dont have the engine speed up enough and dont put enough into swinging the hand crank, it will just stop before TDC and can break your wrist.