How to hand crank start a Yanmar 2GM20

[DownWest]

Used to hand start Listers up to 25hp all the time, but they have big flywheels. Aluded to a couple of posts back, if not quite enough juice to start, decompress and spin up with the starter , then drop one decompressor followed by the other if the first fires. Used that often with low batteries.
A

 

[pampas]

I'm not sure that the (electrical) drag of an alternator makes much difference until the engine is running.
I've spun up few alternators to test them with an electric drill, I would think the engine would be running and developing power by the time the alternator imposes much load, ASSUMING the engine is working well.
I do know that some alternators (maybe not all) can develop damaging voltage levels under no load conditions, with no load and no excitation current, given say half revs. There is enough residual magnetism in the rotor to do this. Maybe not all alts, but definitely some.

So I would never start without a battery loading the alternator.
However, leaving the 'ignition' switch off until the engine is running, will at least delay the load coming onto the engine. Provided of course there is no electric fuel cut off etc.


Many engines have the alternator feed (Via the w/L) switched through the oil pressure switch to reduce the load during starting

 

[Gaffcut]

Short and probably inaccurate answer

What about buying one on those booster charger thingys, sold by Halfords,- a sort of power in a briefcase jobby whiuch you just clip on and Whoosh! Or so I am told anyway. Happy New year.