muzician21 wrote in
:

Have a B&S on a 70's era Snapper 21" pusher with an aluminum deck. I
believe the engine is probably 10 years newer than the rest of the
mower.

Maybe 10 years ago I took it to a repair shop who installed a solid
state unit to replace the points. Even with the solid state ignition
it was never one-pull start, but as I recall it usually started with
probably 3 - 5 pulls. Now it takes probably 20 pulls or more and
monkeying with the throttle. Once it fires it runs like a clock, runs
up and down the speed range fine. It's also easier to re-start once
it's been running - though still not one pull. Doesn't seem to use an
inordinate amount of oil, no discernible smoke out the exhaust. It
gets what I'd call moderate use. I'm in central Florida so it gets run
bi-weekly or so during the rainy months, not at all during the months
of what passes for a winter down here.

I'm mechanically inclined but not well-versed on the theory of this
kind of engine. I've had it broken down far enough to remove and flush
the gas tank, change the points when it had points, replace the pull
rope. I've change the spark plug of course. I know it should start
much easier than it does. Any suggestions where to look, what to
tweak? There isn't that much to it from what I can see, so it
shouldn't be that difficult. I believe this mower has a lot of life
left in it.

Try this: it won't cost you anything and it worked it my case. In fact I
have to do it every year due to poor quality gas.

First drain the gas tank completely along with the hose to the carborator.
Next either *temporarily* plug or otherwise stop any ability for liquid
to come out of the hose. Vice grips on the end works fine if placed right.
Leave the hose attached to the tank however and remove the tank from the
mower. Put about 1 cup of Varsol into the gas tank. Screw on the lid for
the gas tank so it won't leak. Shake the tank vigoursly for about a minute
or so. Drain the fluid from both ends - the tank and the hose.

After a years mowing the filter at the bottom of my gas tank gets so
clogged with gunk that it changes colour from silver to black. You can
check by draining the tank and looking at it carefully if it's visible.

I went for two years having to start it with ether the first time every
year. Even took it in for service with no improvement before I figured
this out. Now it will start on choke first pull when it's 45 degrees F.
Every time.