"trader_4" wrote in message
...
On Friday, June 7, 2019 at 3:43:06 PM UTC-4, Rod Speed wrote:
"trader_4" wrote in message
...
On Friday, June 7, 2019 at 2:15:33 PM UTC-4, Rod Speed wrote:
"trader_4" wrote in message
...
On Friday, June 7, 2019 at 12:42:46 AM UTC-4, Xeno wrote:
On 7/6/19 10:43 am, trader_4 wrote:
On Thursday, June 6, 2019 at 5:39:33 PM UTC-4, Clare Snyder
wrote:
On Thu, 06 Jun 2019 17:08:54 -0400, wrote:

On Thu, 6 Jun 2019 12:45:27 -0700 (PDT), trader_4
wrote:


OK, so here we go again. Last Fall I had trouble with this
Sears
two
cycle leaf blower, where it would not start. Finally figured
out
it
was a stuck piston ring. The ring broke when I tried to get
it
out,
so I cleaned up the groove with a tiny screwdriver, got all
the
carbon
out, got a new ring, put it in. In floated freely. Put it
back
together and it ran fine for awhile, then I had carb troubles.
So,
I bought a new carb from China and it ran better than when it
was
new. I put maybe 8 hours of use on it last Fall. Now it won't
start
again, won't fire.

After exhausting all possibilities, I took it apart again and
the
piston ring is stuck again. Sides of the piston have some
black,
shellac like stuff on it too. Broke the ring again, but have
it
all cleaned up again. The question is why did it foul again?
Some more history, when this was new ten years ago, I should
have
taken it back, because it didn't run well with no choke. So
most
of the time on it, I ran it with half choke. Of course if
they
had screws you could adjust, I could have tuned it, but
instead I
just put up with it. So, first time the ring got stuck, I
figured
it was probably from running it too rich all those years.
After
putting
the new ring in, I probably ran it for a few hours with the
old
carb
and half choke. But after that I put the new carb on and it
ran
beautifully, no choke. I made sure to use a modern synthetic
oil,
mixed to the correct ratio. So, how did it get fouled again
in
just
8 hours? I know I should just put it out into the dump, but
it's
otherwise in fine shape and runs great when it runs and this
has
become
kind of a battle of wills.


Just a wild-ass guess - maybe the original stuck ring
caused some deformation/wear in the cylinder wall
that caused the new ring to stick ?
John T.
Not likely. Are you mixing the synthetic oil to the engine
spec
or
the oil spec?

It was to the engine spec, or close to it. 40:1 I have that and
a
lawn edger, one might be 40, the other 45, I know if one is
different,
I just split the difference. I can check tomorrow and see what
the
oil
says.




Are you using ethanol free gas?

No, I don't even know where to find it around here. I guess I
could
buy the super expensive stuff at HD, but then if it's ethanol
related,
why did it work for 10+ years, but now foul the ring, then foul
it
again in only 8 hours? Also, in the fall, when I was having
trouble,
I did mix up fresh gas and used it within a month or two. So
it's
not
like it had old gas that then ran through it causing the
problems.
It was fresh gas that caused the trouble. I think I recall it
getting
harder to start the last couple times in Dec, then would not
start
at
all just now.

But in general, usually, the gas does sit around. You know how
it
goes.
I have a one gallon
plastic jug, the little oil things come in a size that makes a
gallon.
But after the fall, whatever is left, sits there. I guess I
could
throw
it out. But funny thing here, I took the carb apart and it was
spotless, no sign of anything fouling.



I'd throw in a new ring,
mix ethanol free gas with the synthetic oil (not marine, right?)

No, it's regular synthetic, not marine.


to
the oil manufacturer's sprc - i.e. 50:1 even if the engine says
16:1 -
and add some "sea foam" to the mix according to the instructions
on
the can.
If you are using marine or water-cooled snowmobile oil that
could
be
your problem - weedeaters run a lot hotter than water cooled
marine
engines. The cyl walls won't cause the ring to stick in the
piston.

Thanks.

In the US, the fuel is, for want of a better word, crap. You cannot
*leave it* in the machine and you need to properly *winterise* any
and
all petrol powered equipment. EG.

https://www.briggsandstratton.com/na...-properly.html

The shellac like appearance is from the breakdown of the fuel that
is
remaining in the cylinders. It is normal to run the devices out of
fuel
but with two stroke engines that's a fraught practice. In that case
you
need to use a *fuel stabilizer*.

That's an interesting theory, that the shellac like stuff isn't from
combustion of the fuel, but from whatever is left that later dries
up and hardens. But it doesn't really explain how a new ring
failed in so few hours, while the previous one lasted ten years,
with no change in how I've used it.

Maybe the second one was just a dud ring.

What is a dud ring?

One that isnt made properly so its too easy
to gunk up and jam in the slot in the piston.

It fit, it floated freely in the groove.

But may well have had less free space around it in
the groove or have had a worse finish so it gummed
up much quicker than the original one did. Clearly
there has to be a reason it seized up much quicker
and you claimed that it wasnt what fuel etc was
used or how the engine was used.

It's just spring steel. The problem isn't the ring,
it's that carbon and gunk fills up the groove so
the ring sticks, it binds up in the piston groove.

Duh, but if the ring isnt finished properly it
can gunk up enough to jam in the groove.

Yeah, sure, whatever.

You never could bull**** your way out of a wet paper bag.