On Apr 27, 10:43*pm, "nom=de=plume" wrote:
I read the wiki on diesels, and I think I read that if a diesel is running,
then it doesn't need a spark (e.g., battery energy) to keep running. If
that's the case, then it seems like you should be able to start a diesel by
hand, assuming you have the muscle or leverage. So, in the former case, even
if your battery died - perhaps got wet and shorted out - then the engine
would keep running. In the latter situation if the battery was already dead,
you might be able to crank it to start it.

--
Nom=de=Plume
Older diesels do not need any electricity once they have been started.

They make battery eliminators for small engines that can be started
mechanically by other means. The battery eliminator prevents the
charging system from going over voltage without a battery as a load.
Small motorbikes, lawn tractors, etc can be converted if they have a
mechanical cranking alternative.

It's only practical to start very small engines without some means of
mechnically assisted cranking. So if you're talking about a small
generator or something similar that has a simple diesel engine then
what you suggest may be practical.

I don't think you are going to find yourself in a situation where a
battery has gone from working to failed, and the charging system is
still working, and the engine is still running from it's initial
startup. Diesel or gas. And you are not going to hand crank any
diesel capable of moving a boat. So your questions, while possibly
interesting theoretically, have no practical application.