2 cycle compression ......
 

On 2012-03-27, Steve B wrote:

would hit TDC, or fire with a spark. Does two strokes not have the "POP"
that four strokes have because of their different configuration?

Sounds like you want to know if there is enough compression in yer
2-stroke. When I was a motorcycle mechanic, lo these many yrs ago,
the rule of thumb for both 2 and 4 strokes was: Pull the spark plug.
Put yer thumb firmly over the plug hole, make sure the throttle is
wide open, and cycle the engine. If there is enough compression to
blow air past yer thumb, that's good enough. If not, you need a
rebuild. Typically a bore job and new rings.

nb


--
Fight internet CENSORSHIP - Fight SOPA-PIPA
Contact your congressman and/or representative, now!
http://projects.propublica.org/sopa/
vi --the heart of evil!

2 cycle compression ......
 

On Tue, 27 Mar 2012 03:36:21 +0000, notbob wrote:
Sounds like you want to know if there is enough compression in yer
2-stroke. When I was a motorcycle mechanic, lo these many yrs ago, the
rule of thumb for both 2 and 4 strokes was: Pull the spark plug. Put yer
thumb firmly over the plug hole, make sure the throttle is wide open,
and cycle the engine. If there is enough compression to blow air past
yer thumb, that's good enough. If not, you need a rebuild. Typically a
bore job and new rings.

I've been told that one too in the past (and used it - it is a good
test). I did have a 10HP engine which passed the 'thumb test' though but
still didn't have enough compression to run; that one turned out to have
major damage toward the bottom of the bore, with minor piston damage too
(but rings were intact).

The long-term correct fix was a rebore, but the emergency redneck fix
(more to see if it would even work than anything) was to patch the damage
with epoxy*. Two years later it's still running like that... :-)

* can't remember what I used now, but something rated for high temp and
oil contact.

cheers

Jules

2 cycle compression ......
 

On 2012-03-27, Jules Richardson wrote:

* can't remember what I used now, but something rated for high temp and
oil contact.

Not familiar, it being decades since I was a motor wrench.

One quickie trick is to squirt some heavy motor oil (50-60wt) in the
sparky hole to give the rings some temp sealing power. It will go
away, but often gives jes enough seal to get the engine running.

nb

--
Fight internet CENSORSHIP - Fight SOPA-PIPA
Contact your congressman and/or representative, now!
http://projects.propublica.org/sopa/
vi --the heart of evil!

2 cycle compression ......
 

I've heard of using a squart of two stroke oil, which burns more cleanly.
Same idea.

Christopher A. Young
Learn more about Jesus
www.lds.org
..

"notbob" wrote in message
...

One quickie trick is to squirt some heavy motor oil (50-60wt) in the
sparky hole to give the rings some temp sealing power. It will go
away, but often gives jes enough seal to get the engine running.

nb

--
Fight internet CENSORSHIP - Fight SOPA-PIPA
Contact your congressman and/or representative, now!
http://projects.propublica.org/sopa/
vi --the heart of evil!

2 cycle compression ......
 

"notbob" wrote in message
...
On 2012-03-27, Jules Richardson wrote:

* can't remember what I used now, but something rated for high temp and
oil contact.

Not familiar, it being decades since I was a motor wrench.

One quickie trick is to squirt some heavy motor oil (50-60wt) in the
sparky hole to give the rings some temp sealing power. It will go
away, but often gives jes enough seal to get the engine running.

nb

Here is a trick that seems to be little known, but one that has worked for
me at times over the many years I owned a small engine shop.

For a vertical cylinder engine, remove the spark plug - rotate the piston to
TDC (Top dead center) and then pour in paint thinner. It dissolves carbon
on piston rings and valve seats. Let stand overnight. Then drain oil and
refill with new oil. This will often bring compression up from virtually
nothing to a workable engine. Not a permanent fix, but gets you by. For a
horizontal piston (vertical crankshaft), tip the engine on its side with the
spark plug up.

Bob-tx

2 cycle compression ...... redux
 

Went to the local small engine repair place today to get a couple of other
parts for another machine. He checked the compression, and it was an
astounding 45 psi. So, apparently there are major problems in the engine,
probably rings. Not sure whether to dump more $$$ into this, or just junk
it and get the electric used ones at yard sales for $15.

Oh, wait, I think I know the answer to this one.........

Steve

2 cycle compression ...... redux
 

On Tue, 27 Mar 2012 17:17:31 -0700, Steve B wrote:

Went to the local small engine repair place today to get a couple of
other parts for another machine. He checked the compression, and it was
an astounding 45 psi. So, apparently there are major problems in the
engine, probably rings. Not sure whether to dump more $$$ into this, or
just junk it and get the electric used ones at yard sales for $15.

Pull the head on it and check the bore for damage - typically on these
smaller engines the head gaskets are quite meaty and will come off clean
(and can be reused). Unless, of course, it's a head gasket problem in
the first place...

Oh, wait, I think I know the answer to this one.........

I don't know, I don't like electric stuff - too much of a pain to run
cords everywhere. On the other hand, gas prices... :-)

cheers

Jules

2 cycle compression ...... redux
 

On Thu, 29 Mar 2012 08:04:35 -0700 (PDT), wrote:

On Tuesday, March 27, 2012 8:59:03 PM UTC-4, Jules Richardson wrote:
Pull the head on it and check the bore for damage - typically on these
smaller engines the head gaskets are quite meaty and will come off clean
(and can be reused). Unless, of course, it's a head gasket problem in
the first place...

It's a 2-stroke weedeater. 99.99% chance that it does not have a separate head. The head and cylinder are one piece and bolt to the crankcase. Nearly all small 2-stroke engines have one-piece "jugs."
Stange, NONE of the numerous 2 stroke engines I have floating around
have integrated jugs. They ALL have removeable cyl heads.

2 cycle compression ...... redux
 

On Apr 2, 6:41*pm, The Daring Dufas
wrote:
On 4/2/2012 4:10 PM, wrote:

On Thu, 29 Mar 2012 08:04:35 -0700 (PDT), wrote:

On Tuesday, March 27, 2012 8:59:03 PM UTC-4, Jules Richardson wrote:
Pull the head on it and check the bore for damage - typically on these
smaller engines the head gaskets are quite meaty and will come off clean
(and can be reused). *Unless, of course, it's a head gasket problem in
the first place...

It's a 2-stroke weedeater. 99.99% chance that it does not have a separate head. The head and cylinder are one piece and bolt to the crankcase. Nearly all small 2-stroke engines have one-piece "jugs."
* Stange, NONE of the numerous 2 stroke engines I have floating around
have integrated jugs. They ALL have removeable cyl heads.

My 2 stroke .049 model airplane engines from my childhood had removable
heads. ^_^

TDD

And the simple way to check for bore/piston damage is to pull the
exhausst and take a look.

Harry K

2 cycle compression ...... redux
 

On 4/2/2012 4:10 PM, wrote:
On Thu, 29 Mar 2012 08:04:35 -0700 (PDT), wrote:

On Tuesday, March 27, 2012 8:59:03 PM UTC-4, Jules Richardson wrote:
Pull the head on it and check the bore for damage - typically on these
smaller engines the head gaskets are quite meaty and will come off clean
(and can be reused). Unless, of course, it's a head gasket problem in
the first place...

It's a 2-stroke weedeater. 99.99% chance that it does not have a separate head. The head and cylinder are one piece and bolt to the crankcase. Nearly all small 2-stroke engines have one-piece "jugs."
Stange, NONE of the numerous 2 stroke engines I have floating around
have integrated jugs. They ALL have removeable cyl heads.

i used to rebuild stihl back pack blowers fairly often. They are all
one piece.
--
Steve Barker
remove the "not" from my address to email

2 cycle compression ...... redux
 

On 4/2/2012 10:25 PM, Harry K wrote:
On Apr 2, 6:41 pm, The Daring
wrote:
On 4/2/2012 4:10 PM, wrote:

On Thu, 29 Mar 2012 08:04:35 -0700 (PDT), wrote:

On Tuesday, March 27, 2012 8:59:03 PM UTC-4, Jules Richardson wrote:
Pull the head on it and check the bore for damage - typically on these
smaller engines the head gaskets are quite meaty and will come off clean
(and can be reused). Unless, of course, it's a head gasket problem in
the first place...

It's a 2-stroke weedeater. 99.99% chance that it does not have a separate head. The head and cylinder are one piece and bolt to the crankcase. Nearly all small 2-stroke engines have one-piece "jugs."
Stange, NONE of the numerous 2 stroke engines I have floating around
have integrated jugs. They ALL have removeable cyl heads.

My 2 stroke .049 model airplane engines from my childhood had removable
heads. ^_^

TDD

And the simple way to check for bore/piston damage is to pull the
exhausst and take a look.

Harry K

Actually, all I had to do was look in the exhaust port to see the
piston. ^_^

TDD

2 cycle compression ...... redux
 

On Monday, April 2, 2012 5:10:34 PM UTC-4, wrote:
On Thu, 29 Mar 2012 08:04:35 -0700 (PDT), wrote:
It's a 2-stroke weedeater. 99.99% chance that it does not have a separate head. The head and cylinder are one piece and bolt to the crankcase. Nearly all small 2-stroke engines have one-piece "jugs."
Stange, NONE of the numerous 2 stroke engines I have floating around
have integrated jugs. They ALL have removeable cyl heads.

Quick survey of ten chainsaws, three weedeaters, fourteen gasoline model airplane engines, and two snowmobiles: ALL have an integrated cylinder and head (aka jug) that bolts to the crankcase.

Nothing new has a separate head. You either have some very old equipment or you're making it up.