I have never liked the safety switches often found on rider-mowers. In
fact, in the past I have disconnected them as a nuisance.
I bought a used rider this summer, and wouldn't you know - I was
knocked backwards over the seat back onto the ground by a low tree
limb. I wasn't hurt too badly, but the damned mower kept on going
across the street and across my loving neighbor's yard until it hit
one of his bushes. No damage was done except to my ego.
With my new insight, I have checked and find no sign of any cut-off
switch under the seat. I expected to find one - disconnected or
otherwise not working. Okay, what would be the easiest way for me to
create and install such a switch? Can someone reply with some advice
PS the limb has been removed.
On Sep 1, 8:53 am, email@example.com wrote:
I'd ask myself this question:
If I've never needed a safety switch before this and in fact I've
always disconnected them and the offending obstacle no longer poses a
threat and I'm much more aware now of what can happen, do I really
need to add a safety switch or should I just add this to my list of
bad experiences and vow to keep my eyes open in the future?
If it was me I'd exclaim "Wow, that sucked!" and answer with the
Most of these small motors seem to have a "solid state" ignition. A
magnet on the cam shaft both "charges" the magneto and then opens the
electronic "points." The secondary of the coil produces the high voltage
for the spark coil.
The kill switch is almost always across the low side coil in parallel the
the electronic or mechnical "points." When the "points" open, the coil
maintains the voltage and it's stepped up the the turns ratio.
The "run position" of the kill switch is OPEN. The "kill" position is
ASSuming there is way of stopping the mower short of shorting out the spark
plug then all you have to do is extend the wiring to your seat switch.
Again, arange things so that the switch is OPEN when you are properly seated
and CLOSED when you are off the seat.
While you may see some pretty crappy switches in such service remember that
the peak voltage can easily be in the hundreds of volts. IOW: you don't
want a switch from the auto parts store meant to switch 12 volts DC.
Radio Shack often has "hobby" stuff that might include a single pole, double
throw "microswitch" with a long and flexible operating lever. The long
leverl will permit some overtravel without damaging the switch.
You use the N.C. and the common contacts.
You can either try to rig something on the seat (including a strong spring
that will lift the seat or you can just arrange something as simple as a
rubber band holding the switch level down and a strong string connecting the
rubber band to your body. When your body leaves the lower, you pull and
break the rubber band and the machine stops.
The wrist band switch found on boats and jetskis would work and avoid
modifying the seat. I suspect you could find a normally open one
though most are normally closed. Since it's a rider a normally closed
one might be more appropriate. Most likely the existing key switch
turns on 12v to the ignition. So a normally closed switch could be
used in series with that wire.
Some riders require you to hold a pedal down to go. Then when you
fall off it quits moving. That's a better soltion as you don't have
to restart it if you have to get off for a moment to move something
that's in the way.
Problem there is that I often find myself shifting my weight when I'm
doing the ditches - both for balance and to keep the mower from losing
traction; I'm not sure how reliable a seat switch would be in those
situations (my lawn tractor's old and never had one, and I've never used
a more recent mower that does).
What would maybe work is some sort of kill switch based upon a plug that
had to be inserted into the dash, connected via a short cord and clip to
my belt. That way if I fell off, the machine would still stop because the
plug would be pulled out, but I'd still be able to move around in the
You could also "invent" your own with a 1/4" phone jack. Just short
the terminal in the male half and attach a cord. Probably get a
female dash mount socket and a male jack from radio shack for well
I used to do the same thing with a 1/8" one on RC sailplanes planes as
an off switch. Hung a red banner off it. Nothing worse than letting
a plane loose and then figuring out you didn't turn on the receiver :-(
On Wed, 01 Sep 2010 10:23:59 -0400, Kurt Ullman wrote:
Probably; I've certainly heard about that sort of setup on various things
over the years. I suppose the danger with a mower is that you might fall
off and the cord might get wrapped around something that was rotating -
so maybe it's not such a good idea :-)
Something that you have to press with your foot isn't too bad - except it
takes me 2-3 hours to mow our lawns, and I don't think I could keep my
foot in one spot for that long.
Tricky problem I think, with drawbacks to ust about any solution. As
someone else said, it's a pain that a kill switch does kill the machine,
rather than taking it out of drive - but the latter would be difficult on
a machine without hydraulic drive due to the forces needed to engage/
(further thought: I actually get off our tractor sometimes. We've got a
couple of low-hanging plum trees with rather painful branches, so I drop
the revs down, put it in first, and just let it run under them at a
crawl. Grass under there doesn't grow fast, so it only needs it a couple
of times a season. Difficult to do that with any kind of safety switch,
Not to mention disengaging the PTO, some have electric clutches and that
would make it easy, but on ones like mine you need to disengage and move
the PTO lever. Stopping the engine would take care of that.
Ask someone local at a small engine repair or lawn equipment repair for a
parts layout. It's very dumb to remove that switch and you found out why.
I left mine intact on the Deere tractor but I defeated the button that
kills the motor if you reverse without pushing it.
re: "... I defeated the button that kills the motor if you reverse
without pushing it"
My son's rider has a position on the ignition that you have to turn
the key to in order to run it in reverse.
You need to turn the key one position towards Off to use Reverse. It's
not so bad.
He did defeat the under-the-seat-kill-switch for all the reasons many
On Sep 1, 8:53 am, firstname.lastname@example.org wrote:
Each mower is different. Somes seats have a tab that open/closes the
kill switch (depending on how it is setup). The switch may no be
visible except from underneath.
If you still don't fine it and want to add a new one, there are many
ways to do it. Some good suggestions were posted here already, but
other ones are available too.
Usually the engine has a magnteo on the flywheel (not the cam shaft
becasue the camshaft only turns at half the speed of the crank). when
the magnet onthe flywheel passing the coil, it creates a spark at the
right time. There is one wire running from your coil which is used to
ground out the coil and not let it fire, thereby killing the engine.
By tapping into this wire, you can rig up a kill switch to ground out
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