[brlug-general] re [OT] solenoid question - questions resolved

[Doug Riddle]

It seems we have more scientist than mechanics on the
list.  I haven't worked with solenoid ignitions in
over 20 years, but I sketched the diagram, traced the
wires (God, I hate engineers) and reached my decision
as two physicists wrote me to explain why I the way I
knew was the way it worked, had to work that way.  You
guys are no slow coaches.

I used to know small engine backwards and forwards,
but it has been a long, long time since I needed that
knowledge.  After a few hours of wire mapping, knuckle
busting, and greasy hands, a mental book slid out of
long-term storage, and the lawn tractor is OK.  Or, it
will be come   tomorrow.  I lost the light, along with
a 7/16 inch bolt, and the energy to finish the job
this evening.   I found the bolt, but elected to alter
the body a bit.  The battery well is now removable. 
There is a nice sized opening to reach into the steel
box that is the rear frame of the trackter.  If I
hadn't had to spend the better part of an hour and a
half looking for the stupid nuts and bolts I knocked
off the back of the darn thing I'd have mowed some
weeds today.

If anyone has a deep need to know how the ingnition
solenoid functions, and how it is connected to the
rest of the vehical, write me off-line.  I prepared
some text to post and sent it to a couple of people to
proof for logic errors.

A solenoid is a pretty simple device.  It is a 12 volt
circuit with three states:
Key on - two (through) posts on & magnet off - One
live circuit.
Key start - two (through) posts on & magnet on - Two
circuits active, one engaging the starter, and one
providing power to the engine.
Key off (or removedZ) - no circuits active. magnet
off. Battery isolated.

Write me off-list for the in=depth version of a basic
small engine ignition system.

Again.  Thanks@



=====
Warmest Regards,

Doug Riddle
An opptimist thinks the glass is half full.  A pessimist thinks it is half empty.  A realist knows that someone is going to have to wash the glass.  I am a realist.  I buy plastic drink cups.

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