On Tue, 27 Apr 2010 19:43:02 -0700, 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.

I own a small diesel generator (3.5KW) set that has a pull rope to start
it, or it can be cranked over with a battery. I have jumper cables
permanently attached so if it comes time to use it I can quickly attach
them to the yard tractor to start. I then turn off the key that disables
the charging system. Disconnect the the battery cables and can then
connect it to 120/240 volt for standby use. It is mounted on wheels in a
carry frame for use during a hurricane.

Once it is hot, it can be shut down and will restart without the battery
if you can get it to the correct rotation position to pull it through a
compression stroke with the fuel injection pump in the run
position.(Easier to get the tractor to jump it again.)This is the manual
function to shut it down. No electricity required to keep it running.

Once running, the generator works using residual magnetism to flash the
fields to generate AC voltage. The battery is not needed for this to
function.

It was originally manufactured to hold a battery, but because this is only
used when required I don't see any reason to maintain another battery that
can be monumentally replaced using the lawn tractor battery to jump start
it.