Bleeding Yanmar GM Series Engines:
Open the small bleed screw on top of the engine mounted fuel filter and operate the fuel lift pump by hand. If the hand priming lever doesn't have any resistance through any of its travel, rotate the engine crankshaft through 360deg. Use the starter motor or crank handle. There is no resistance to the hand priming lever because the internal actuating arm is on the top of the cam that drives it. Rotating the engine crankshaft 360deg will turn the camshaft 180deg, the arm will now be on the back of it's cam and you should feel resistance when operating the hand priming lever.
After the fuel filter has been purged of air, close the bleed screw (don't do it too tight, it's only little) and open the one on the fuel injection pump. Again, after the air has been purged, close the bleed screw.
The engine should now start, if not you will have to bleed the high pressure side as follows:
Crack the pipe nut at each injector, open the decompression levers and rotate the engine with the starter motor.
When the air appears to have been purged (the fuel looks clear, not whitish), tighten the nuts firmly, close the decompression levers and start the engine. Check for leaks and clean up any spilt fuel.