My project is to replace the rings in the old 8237 lawnboy. The
problem I am having is pulling that piston out of the cylinder. It
pumps through the cycle without friction, but when trying to pull the
piston out of the cylinder it gets hung up..
How can it be pulled out? What technique do I use? Is a special too
It wore the head larger than the lower end of the cilinder. Even if you
get it out the steel rings probably have less wear than the aluminum
head, and stock will be undersized. I guess use force, hone out ridge
and measure for correct ring size, or throw it in the trash and buy new,
You may have a ridge on the cylinder wall up near the top caused by the
bore wearing in the region the piston ring(s) sweep through. That's
enough to stop a piston ring moving up and out.
Push the piston down all the way and see if you can reach in and feel a
ridge with your fingernail.
If you find a ridge, Google for "cylinder ridge remover", a tool like
the one pictured on this page:
i just pull it out, you think theres a ring ridge or something
on the lower cyl the rings are catching on? maybe a brass rod thru the
plug hole would tap it out. lucas
Last I read about this, in 1970, the rings wear away some of the
cylinder, but the rings never get to the top, so that part is original
There's a tool to grind it away, but it might have been a power tool
attachment. I';msure there's one for lawn mowers too.
You'll probably have to get oversize rings, iiuc. I suppopse they
make those for lawn mowers, but I'd loook into it before going much
Or maybe I mean, for cars, I think they redrill the cylinders, and
maybe put a sleeve in to get it back to the original size.
But like I say, I haven't read about this since 1970 (wrt cars) and
I've never done it.
Remove NOPSAM to email me. Please let
me know if you have posted also.
It's called a cylinder hone. It's used to smooth the surface of the
If the mower is so far gone that oversize rings are needed, it's time for a
To get the piston out, use a wood dowl on the top of the piston, placed
directly in the center, and strike it with a hammer.
TO all who have already replied;
Yeap, the reamer is made for removing the ridge, the honer will only
take out small bumps--I guess. Look at the link it shows the tools.
I got one more question on this topic. If the engine seems to be
giving good compression and works seemingly fine, who can tell me what
danger there is in leaving the current rings in there and just running
this engine till it quits?
Would there be *any* benefit of installing new OEM rings at this
The reason that I ask is that the reamer costs $50.00 and this is
raising the cost of repair, I dont think I will ever use that reamer
again in my life.
Thanks again guys,
you cant use a ridge reamer on a lawnboy 2 cycle engine, the "head"
is made on the cylinder ,so you cant get to the ridge to ream it. ive
seen many a good engine ruined by a novice with a ridge reamer. good
compression on a lawnboy is 135-150. there are oversize pistons if you
want to have the cylinder bored. if you got it apart, go ahead and put
new rings in ....lucas
Lucas is blowing smoke! No OS rings or pistons for your Lawn Boy. Also the
compression for your engine should be about 80 PSI. I have rebuilt a ton of
them. I owned a repair shop for 5 years. New rings are a good idea beings
you have it apart, BUT if the cylinder is worn, it is shot! New rings in a
badly worn cylinder is better than old rings, but it is a waste of time to
repair it if it is worn out! Do it correctly or you will be wasting you time
and money. New parts for Lawn Boys are relatively cheap.
Their are enough used Lawn Boys out there so used parts are plenty. In fact
I have never bought a new mower in the 15 years I have owned my home. I like
Lawn Boys so if I see one in the trash I check it out and maybe drag it
home. I gave my first Lawn Boy to my neighbor, a '74 model, he still uses
it. I have replaced it with a mid 80's model I picked up out of the trash,
brought home and tuned up. Many people are of the throw it away mentality so
I find them with little wrong with them. I have three Lawn boys in the
garage right now, although they all run I only use the newest one.
Did you get the piston out? What was the hang up?
top post for ease of reading...
I am re-thinking taking the piston out, because it seems like a lot of
work, for little gain. From what I understand the cylinder is just
about worn out, so my perceived effort of replacing the rings doesnt
outweigh the expected lifetime of the cylinder.
I havent gotten the piston out yet, I will be heading to Home Depot
later today for the dowel if I decide, with your help, if taking it
out is a good idea in my case.
I question going any father with this project if the cylinder is worn!
I would hate to see you throw more money at it if it is in poor shape.
Personally, I would get the piston out, see what the cylinder looks like,
then decide. If the cylinder is ok, rings don't cost that much. You may have
If the head and cilinder are one piece then he will never get the piston
out, the rings will be worn in a grove, so basicly you throw it all away
when compression is shot, but at replacement parts cost retail and
bearings etc etc, ring compressor and other tools needed he is probably
at the cost or above of a factory new engine, so run it till its toast.
For l;ongest life use a synthetic at 32-1 and keep the air filter clean,
and rpm down.
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