A Toro with a small 4cyc suddenly will not start. It 'kicks back" when
you try and start it. A friend suggested that perhaps the flywheel had
sheared it's pin and the timimg is bad.
I took the cowling off and I'm not sure if it's sheared or not. I
I'd have to hammer it off to take a closer look.
The fly wheel mounted magnet passes over the pickup twice for every
one cycle. Is there something that shorts out the
energy durning the non firing exhaust cycle?
Could the ignition be 180 out? On one pass, as the
magnet passes over the coil, the value is wide open.
On the other it is closed.
DO NOT HAMMER the flywheel. You need a puller. Rent, borrow one or bring it
to someone to remove. Most likely you hit something with the blade which can
shear off the flywheel key. This is very common. It only needs to move a
fraction to put the timing off.
TDC is not on the exhaust stroke, but the power stroke [long time?].
Stick a long pencil (any up-stroke of piston) in the plug hole (plug
out - wire away), rotate the strokes by hand TDC should/will have both
valves closed. Pencil pushed out. Like I say, long time.
TDC needs both valves closed to fire....
"Well, it doesn't happen all the time, but when it happens, it happens
The person who wrote about hammering the flywheel is correct,you must also
never hit the top of the crankshaft where the nut is.The reason...the
threads on the top will pean over and or you can break off the threads
making your lawnmower into a very expesive paperweight
also never use a 3 armed puller on the flywheel it will only break your
depending on the type of engine (you said toro)that is the make of
lawnmower deck not the engine.
you must make an effort to see and get the model number--ie;briggs&stratton
100902 or tecumseh Lev80
then with the proper text book and the proper tool you can learn how to do
this simple repair.
one last thing,the blade hub the part that the blade connects to has on
some models a half moon key known as a woodruff key that could also bee
sheared.inanycase please remove the spark plug before attempting any
hoping this is helpfull.
larry the small engine mechanic
I won't say it's good practice, but there are plenty of small engine
repair shops that remove flywheels from B&S engines without using a
puller. Once you see the technique, it's easy, really... provided you
have 3 hands.
I got a knock off tool, which slips over the end of the shaft. And two
for Tecumseh, as they have two different thread patterns on their
Big screw driver under the fly wheel, and give it a good whack on the
top of the knock off tool. So far, works slick as can be.
Now, to the original poster. Sounds like you did hit something and
sheared the flywheel key. With the old points ignition, there was no
spark when the flywheel key sheared. With the new electronic
ignitions, they don't care. Yes, there are two sparks. One is in the
compresson stroke, near TDC. The other one is wasted, in the exhaust
stroke with the exhaust valve open, and the exhaust gasses blowing
Christopher A. Young
You can\'t shout down a troll.
HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here.
All logos and trade names are the property of their respective owners.