I've got a riding mower with a Briggs and Stratton 14.5 HP engine. It
froze up the other day when my daughter was mowing. I suspected that
she'd let it run out of oil. The oil was really low, so I filled it
up. I managed to get the engine to free up, but there seems to be
something that stops it from turning freely. I turn it by hand and it
turns until it appears to hit something and then won't turn any more
in that direction. I've got the blade pulley disengaged, so that's
not the problem.
No, get a new daughter <LOL>
Seriously, you probably siezed the piston rings, and the cylinder wall
has a groove or ridge. My father did that once with a 3.5 HP briggs.
I took the head off and pounded the piston down with a brass hammer.
Then i greased the piss out of the cylinder walls and spun the blade
until it spun easily. There was a noticable groove in the cylinder
wall, but I put the head back on it, and it started. It smoked pretty
much at first, but an hour later it ran good and the smoke was
minimal. This happened about 15 years ago. I now have that mower,
and it still runs.
I'd start by pouring a little oil in the spark plug hole. Leave the
spark plug off the engine, and spin the engine with the blade. When
you get to the tight spot, work it back and forth, and add more oil.
Flip the whole mower over for a second to get the oil to the bottom of
the cylinder too.
If you cant loosen it up that way, I'd tear off the head, look at the
cylinder wall. Actyually, the best would be to pull off the pan too.
You could also have a scored rod bearing, or a bent lifter rod, or who
knows what else. Those 11 and higher HP engines are notorious for
having the rod bearings go bad. I had one that just blew the whole
engine apart. Mine occurred because the pan bolts came loose from
vibration, and all the oil dumped out within a few minutes. The next
thing I knew, the mower sropped and there was a chunk of the block
laying on the lawn. The entire rod was blown to shreads inside the
engine. I had to replace the whole engine. Mine was the 11HP.
So, if I were you, I think I'd check the bearings. A new bearing, and
or rod is cheap, but a crankshart is half the price of a new engine.
Add to that the cost of a new block, and you may as well but a whole
On Fri, 09 Apr 2004 22:30:12 -0500, email@example.com wrote:
I wanna see him flip the whole mower over... he said it's a riding
seriously... without seeingi t, it would be impossible to say what
the problem is, since every motor will will behave differently when
run out of oil. Some might just sieze up the rings as yours did...
some might throw a rod, etc...
You happen to have been lucky and got yours to work without putting a
lot into it, but most aren't so lucky.
I have yet to see a riding mower engine seize in the piston rings. The
connecting rod/crankshaft journal is usually the first thing to go,
occasionally the top main bearing if it is a vertical shaft engine.
Sometimes the crankshaft can be salvaged, cleaned up. A nasty deposit of
aluminum connecting rod on the rod throw is a good sign, throw is less
likely to be scored then. New rod, $15 Stens or Maple Grove, $25 - $30 from
B&S. Turn Crankshaft, if needed, in this local, $35. Gaskets, seals, rings,
another $25 - $35 depending on where you get them. May want to check your
local NAPA Store.
To find out how to easily clean aluminum rod deposit from crank throw,
just sieze up the rings as yours >did... some might throw a rod, etc...
when i ran out of oil in my toro mower about 25 yrs. ago.. the engine
would move but not start.. the reason is that when you pull the rope the
crank would move but the crankshaft was broken and it just stayed
there... you probably have a broken piston rod and it is hitting the
crank when you move it.... one way to find out is to remove the spark
plug and then try to start it and if you feel no pressure you know that
the piston is not moving....
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