Lawnmower engine clutch broken
 

Tecumseh vantage 50 - broken pawls
Al-Ko BM 875 II
Bought this brand new, but on Ebay from a guy in Italy, less than half
the price including delivery. Unwanted or surplus stock or maybe he
worked in the factory and he has access to the factory rejects......
who knows, I certainly don't.

It took a while to start at first, but once running it was ok, and
after running a few times it became easier to start. Then the
problems came....... often during starting the pull cord would come to
a complete and abrupt stop causing me pain. After only a few hours
running & starting it stopped starting, removing the starter cover,
both pawls broken out and lost. Amazed to see they were only located
in a plastic pulley wheel with thin plastic walls 2mm thick - the
plastic walls had broken on both pawl housings. Found new starter
assembly online but reluctant to buy and fit as surely same problem
will happen again? What to do? Why does engine yank on the starter
cord like this?

I just had a thought maybe the sudden yank on the cord was the starter
spinning without the pawls going oput then all of a sudden the pawls
sprang out to engage - that would do it, but I don't know if that is
mechanically possible, I mean I can't remember how the pawls opened
outwards whether by cetrifugal force or was it just by tensioning the
pull cord they came out without any spinning/centrifugal force.

The alternative was the compression stroke on the engine was jamming
it up.

I guess it's hard for you guys to offer advice without further
investigation by me...... i.e buying a new starter mechanism and
fitting it and trying to come up with more answers as to what the
problem is, so we can finally solve the problem.

The other solution I'm loooking at right now is making my own fixed
pulley which I'm going to securely fix to the crank/starter cup and
then there won't be any pawls to fowl anything up

Any thoughts?

Thanks

Lawnmower engine clutch broken
 

I just had a thought maybe the sudden yank on the cord was the starter
spinning without the pawls going oput then all of a sudden the pawls
sprang out to engage - that would do it, but I don't know if that is
mechanically possible, I mean I can't remember how the pawls opened
outwards whether by cetrifugal force or was it just by tensioning the
pull cord they came out without any spinning/centrifugal force.


I can sort of answer this right now, looking at the broken starter on
my desk, it is clear how it works, it's not centrifugal force. There
is a steel plate which somehow stays still as the cord is pulled, as
the steel plate remains fixed and the rest of the pulley and pawls
begin to rotate, a couple of little protruding lugs on the steel plate
will engage with the pawls forcing them outwards, when they were
fully extended and engaged with the cup flanges the force is
sufficient to then turn the steel plate against it's resistance -
quite clever really.

Perhaps what was happening was that I pulled the cord the starter spun
around but the plate did not remain fixed so the pawls did not come
out. Then as I was pulling the cord out fast, perhaps the plate
suddenly fixed - the pawls came out and jammed onto the cup flanges.

So the answer would be to buy a new starter and make sure to engage
the pawls and the engine was engaged before putting real force onto
the starter cord.

Lawnmower engine clutch broken
 

On 11 Apr, 23:30, freepo wrote:

So the answer would be to buy a new starter and make sure to engage
the pawls and the engine was engaged before putting real force onto
the starter cord.

However maybe my memory is failing me (it broke last summer) and
maybe the pawls did engage and turn the engine as I pulled the cord
and then something happened to jam the engine. - Now that I think
about that, when I looked at the top of the engine today I did notice
some damage to the engine casing (which spins around ) Perhaps
something got jammed as it was being started, but then why no jamming
when the engine was running, who knows, needs more thought, and maybe
need to buy new starter and see what happens.

Sorry for the babbling post.

Any thoughts on this in general?

Lawnmower engine clutch broken
 

freepo wrote:
On 11 Apr, 23:30, freepo wrote:

So the answer would be to buy a new starter and make sure to engage
the pawls and the engine was engaged before putting real force onto
the starter cord.

However maybe my memory is failing me (it broke last summer) and
maybe the pawls did engage and turn the engine as I pulled the cord
and then something happened to jam the engine. - Now that I think
about that, when I looked at the top of the engine today I did notice
some damage to the engine casing (which spins around ) Perhaps
something got jammed as it was being started, but then why no jamming
when the engine was running, who knows, needs more thought, and maybe
need to buy new starter and see what happens.

Sorry for the babbling post.

Any thoughts on this in general?

It wouldn't be the first time something has jammed in a pull cord system
and buggered it.

get new parts, understand how it shpould work, and if it does it again
because its crap design, fix to work, sell on e-0bay and get a decent one.

Lawnmower engine clutch broken
 

On Mon, 12 Apr 2010 09:06:33 +0100, The Natural Philosopher wrote:
It wouldn't be the first time something has jammed in a pull cord system
and buggered it.

get new parts, understand how it shpould work, and if it does it again
because its crap design, fix to work, sell on e-0bay and get a decent
one.

It's possible it's intentionally designed as a weak-but-replaceable link
in the system, same way that the B+S engine in my lawn tractor uses a
plastic gear on the starter motor - they get chewed up after a few
seasons, but I can just walk into the local farm supply shop and buy one
off the shelf cheaply. Better that than needing to replace the flywheel
every so often, I suppose.

cheers

Jules

Lawnmower engine clutch broken
 

freepo expressed precisely :
Sorry for the babbling post.

Any thoughts on this in general?

It sounds as if you might be just yanking the cord. What you should be
doing is pulling it gently to the point of compression, taking another
bite and then giving it a firm pull.

--
Regards,
Harry (M1BYT) (L)
http://www.ukradioamateur.co.uk

Lawnmower engine clutch broken
 

"Harry Bloomfield" wrote in message
. uk...
freepo expressed precisely :
Sorry for the babbling post.

Any thoughts on this in general?

It sounds as if you might be just yanking the cord. What you should be
doing is pulling it gently to the point of compression, taking another
bite and then giving it a firm pull.


ITYM.. pulling it gently OVER the point of compression.

--

Mike

Lawnmower engine clutch broken
 

On 13 Apr, 17:33, "Mike" wrote:
"Harry Bloomfield" wrote in message

. uk...

freepo expressed precisely :
Sorry for the babbling post.

Any thoughts on this in general?

It sounds as if you might be just yanking the cord. What you should be
doing is pulling it gently to the point of compression, taking another
bite and then giving it a firm pull.

ITYM.. pulling it gently OVER the point of compression.

--

Mike

This is correct. I didn't know how to start it before, but now I do
and it is working fine.

I fixed it with a homemade fixed pulley which is now bolted to the top
of the engine. I turn it beyond the compression point, wind my rope
around it and pull.
It's working so well I'm sure it would work equally well with a new
shop bought retractable rope starter clutch & pawls system as was
fitted originally, but I've made my pulley now and I'm in no hurry to
buy a new pullstart for it.

A pity the instruction manual didn't explain how to start the engine
in a way that would not cause damage to the pullstart.

Lawnmower engine clutch broken
 

A pity the instruction manual didn't explain how to start the engine
in a way that would not cause damage to the pullstart.

My other (smaller) lawn mower has no problems starting the engine from
any position. I guess it's because the engine is smaller, smaller
compression easier to start.

Lawnmower engine clutch broken
 

On Mon, 24 May 2010 02:53:21 -0700 (PDT), freepo wrote:

I fixed it with a homemade fixed pulley which is now bolted to the top
of the engine. I turn it beyond the compression point, wind my rope
around it and pull.

I hope you are *very* sure that the rope will *always* release from
the pully as you turn the engine over. If it doesn't it won't half
give your arm a yank and possibly pull you off your feet when the
engine starts...

--
Cheers
Dave.

Lawnmower engine clutch broken
 

We were somewhere around Barstow, on the edge of the desert, when the
drugs began to take hold. I remember "Dave Liquorice"
saying something like:

On Mon, 24 May 2010 02:53:21 -0700 (PDT), freepo wrote:

I fixed it with a homemade fixed pulley which is now bolted to the top
of the engine. I turn it beyond the compression point, wind my rope
around it and pull.

I hope you are *very* sure that the rope will *always* release from
the pully as you turn the engine over. If it doesn't it won't half
give your arm a yank and possibly pull you off your feet when the
engine starts...

Or turn into a flail with amusing conseqenses for the ankles.
Nah, such heeby-jeeby starter pulleys were dead common for decades.