I have an old Montgomery Ward, with a Tecumseh engine, snow thrower
that keeps running when I take the plastic key out. I turned it off by
turning the choke down. I notice the other day that it was leaking gas
( I think from the carb) when the key was left in and seemed to have
stopped when I took it out. How does the key work and is this
something I need looked at or fixed??
Mostlikely just shorts out the magneto, as likely should happen when
throttle is moved to the very slowest position. AFAIK such keys are
merely safety devices, to keep kids from getting hurt.
On such engines, nothing so sophisticated as key shutoff of fuel
Fuel leak likely from leaking o-ring, like around main mixture
or leaking float valve, or perforate float. Carb-rebuild time.
If it has a plastic key then it most likely has a metal
contact inside that has lost some of its spring.
Basically when you pull the key out the metal contact inside
is suppose to touch the ground and short out killing the ignition.
Since most people like to leave the key in for all these years
the metal contact that is suppose to short out looses its spring
and doesnt work right. You can remove it and bend it again to
give it some spring again. Easy fix.
Now the carb problem.... You might have an issue where there
is a little dirt in the needle valve. If the carb hasnt been cleaned
years I would bet that's the problem. I'd try cleaning it out with a
carb cleaner. Otherwise a small carb rebuild wouldnt hurt either.
(basically clean it out and replace all the old gaskets)
I would also check the float and make sure its not filled with gas.
Sometimes they fail from a pinhole leak and the float doesnt work
the way its suppose to anymore.
On ours the wire attached to a shorting contact on the lowest setting
of the throttle broke off.
So we used to throttle down and then choke the engine to stop.
Finally last year doing some other maintenance we reattached the wire
and now we just push the throttle right down to where it contacts and
shorts out the ignition.
IIRC it is the same circuit that is grounded (shorted out to frame) by
removal of the plastic 'key'?
Our is a Tecumseh engine.
The carb bowl is located on the bottom of the
carb. It normally has a 1/2" nut on the bottom
of it. I would turn off the gas (if it has a cutoff switch)
If no fuel cutoff switch, just use a good plastic cup
under the carb to catch the gas. Once drained you
can take off the carb bowl. In there you might see
some dirt on the bottom of the bowl, clean it out.
The needle valve is visible when you pull the
float all the way down. The needle looks like a little
metal pencil with a wire attached that connects to the
float. Easy to get out, a little more tricky to get back
in. Clean the needle valve off with a carb cleaner....
I can go on here about how to do a basic rebuild...
Sound like something you want to do????
If not that's ok.
A quick way of taking care of a leaking carb can also
be just to put in a fuel cutoff switch under the gas
tank of that snowblower. That way when its
off no more gas pours out. When you run it, its
not much of a problem at that point because the
gas is properly being sucked into the motor.
I think you are relating the unrelated, the fuel leak was likely a
result of shutting it off with the choke, and it stopped because it had
leveled out, not because you pulled the key. The no shut off is as the
other posters have explained probably due to the contacts separated by
the key being tired & no doubt an easy fix. If the key enclosure is
impenetrable, you could always replace the whole thing with almost any
sort of a switch, a key switch preferable if youngsters are a problem.
I bought a used mower that had a piece of spring steel bolted next to
the spark plug, you push it with your foot to shut down, crude but
As other have said, the switch is nothing more than a simple shorting
operation. Something (probably a spring) is no longer shorting out.
Simplest fix is to just pull the wire off the switch and fasten it so
you can just push it against the machine to make a short. A remote
possible is that something has pulled the wire loose leading to the
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