In my misspent youth, I tried big gear pullers on mower flywheels & as
described they will flex and still not release. I have seen one bend,
& put it right back into service. It never showed any sign of the
abuse and served until the piston ring seal was so poor you had to mow
with a screw driver in your pocket to adjust the mixture as it warmed
up, at which point the entire rig was retired. I think the fragility
of the flywheel is badly overstated.
Using a gear puller alone (by cranking it hard rather than using a
hammer) will warp the flywheel and perhaps cause stress fractures.
When you use a proper prybar and hammer, the prybatr is lifting at the
center, not an inch away from the center. The tip of the prybar should
be against the crankshaft.
The OP now has a flywheel of very questionable safety.
Darwin was a pretty smart guy.
Asking the same question here, and getting the same answers, isn't
going to change anything.
To add something that hasn't been mentioned (or I didn't see it). The
inertia delivered by the hammer affects the crankshaft, not the
flywheel (you are preventing it from moving).
At the end of the day you will just have to accept the fact that it
does work when done properly and won't cause damage to anything.
I understand your concern!
At first, I leveraged UP with the prybar on the aluminum engine, then moved
about 60 degrees and leveraged again (all the while uselessly banging DOWN
on the flywheel puller contraption from ACE on the flywheel).
When I moved the third 60 degrees, I didn't realize it but now I was at the
front of the mower where the carberator and air filter are, which has a
plastic pipe (painted the same color as the aluminum engine) which is the
In just a split second, the plastic pipe collapsed, along with a bolt which
snapped in half holding it to the opening for the intake valve.
It was exactly at that point where I realized the advice to bang DOWN on
the crankshaft while lifting UP on the flywheel (thereby leveraging DOWN on
the soft engine parts) was sheer folly.
It was only then I started wondering about the logic of it all. Of course,
prying UP makes sense to remove a flywheel ... but what does banging on an
immovable crankshaft going to do?
Try it.... has worked for me, for years. Yes, the
crank shaft goes down.
The fit between the flywheel and the crankshaft is a
slow taper. You only have to bump the crankshaft
down 1/8 inch or less, and then the friction fit between
the two shears. And the flywheel lifts off.
I rather doubt that anyone has advised to bang down
on the flywheel.
On Mon, 12 Jul 2010 09:55:16 -0400, Stormin Mormon wrote:
One end of the crankshaft is sticking up in the air with the nut loosly put
back on (to protect the threads) while the other end is firmly attached to
the lawn mower blade. The piston is in the middle.
Where "down" can it go?
That's a LOT of distance for an immovable flywheel. Do you bump it back UP
1/8th of an inch when you reassemble?
I agree. What everyone said (and what utterly failed for me) was to pry UP
on the flywheel and bang DOWN on the crankshaft.
What worked (for me) was to tap the pre-existing holes and lift up on the
flywheel leveraging on the center of the crankshaft with a harmonic
balancer puller with two 1/4 x 20 bolts and washers (that bent like potato
chips from the force). :)
Why don't you just accept the _fact_ that it has worked when done
properly since B&S engines were first built? That it is also done by
almost every small engine mechanic that has ever worked on them? You
have been given clear explanations on why it works, You are just being
obstinate in refusing to believe them.
On Sun, 11 Jul 2010 21:19:22 -0700, James H. wrote:
They make a tool you can screw on the end of the crank to bang on so you
don't mess up the thread at the top. The physic is shock as in an impact
wrench will drive the screw tighter or looser with less effort and less
chance of breaking things. In the plumbing business there is the term
"warming up a pipe joint" when using steel pipe and fittings to loosen
the joint by banging on it when you can't wrench it apart. Same thing
with a lid on a glass jar that you can't loosen. Smacking it down on a
hard surface loosens it enough that you can then unscrew it. They are all
re: "Same thing with a lid on a glass jar that you can't loosen.
Smacking it down on a hard surface loosens it enough that you can then
unscrew it. They are all interrelated."
I always smack the bottom of the jar with the heel of my hand and
listen for the "crack".
It's my understanding that that releases the vacuum that keeps the jar
I'm guessing that there is no vacuum involved in the removal of a fly-
On Mon, 12 Jul 2010 14:57:21 +0000 (UTC), Jeff The Drunk wrote:
I bought that tool; it was useless.
While this shock and awe effect didn't work for me, I do understand what
Basically, from Physics 101 back in college, dynamic friction is less than
So, what you're saying, I think, is by banging on the flywheel (actually
banging on anything would work as well), you set up vibrations, which allow
things to move with just a little bit less friction.
Well, at least that explanation makes sense. It didn't work. But it makes
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