Beetlejuice
Addicted to ArboristSite
The 250 purrs like a kitten.. No chance to look at the 1-50 yet. Still waiting on my wife to purr.. Maybe tomorrow
McCulloch Chain Saws
- Thread starter Bruce Hopf
- Start date
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Another question for you good fellows. Are all 54cc 10-10 cylinders the same?
Got the pm800 for 135nz 
Got the pm800 for 135nz
Great. Ron
Beetlejuice
Addicted to ArboristSite
The 1-50 has life.. Needs to be force fed for now, but got spark..dont know how long it sat, but chain was on backwards and upside down.
Ron and I were cutting today. We cleaned up a old Locust that Ron had fell a month or so ago. Here is a few pics of our day. This is Ron with his PM800.
Brian
Brian
Darrin Cromwell
New Member
I am trying to Identify my mac model no. 6000004 service no. 12-20970 to no avail. It's seems to be a mac 10-10, but those numbers don't exist anywhere I've looked. Will you help me post my question please?
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Sent from my SM-T377V using Tapatalk
10-10A
600004?
Good to see one in the wild.
Walter Glover
ArboristSite Guru
In the quest for understanding figured some actual numbers for piston skirt leakage might clear things somewhat. Setup a rotameter to measure flow out the skirt/cylinder clearance. Just off bdc it started at 1.5 scfh with 7.5psi applied 30 degrees up it went to 2.7 and at 40 it was 3.2scfh. Last flow was 4.4 about a quarter inch before the intake opened. So those numbers meant next to zero to me at that point so needing a second 'opinion' I tore down my cp70. Applied the same pressure and swept the piston through the same range and got one reading of 1.2scfh no matter where i checked. That made it more obvious how bad the sp80 condition is. So might try the new piston if the fit measures ok. Here is a pic
might explain few hard startin but good runnin saws.
Walter Glover
ArboristSite Guru
Another test for the tool kit for sure. Saw with good compression and good seals but ran like crap.
What I initially thought to be flooding was actually spitting g due to this poor skirt fit. Will retest tomorrow with a new piston.
What I initially thought to be flooding was actually spitting g due to this poor skirt fit. Will retest tomorrow with a new piston.
It's a 10-10A made from 12/67 to 2/70
Walter Glover
ArboristSite Guru
CP70L back together and fired up first pull. Runs and idles swell
Now more ripping into the SP80
Edit
SP80 piston skirt measures 2.050" and bore measures 2.062"
Chainswr aftermarket piston measures 2.060" so much better for sure!
Figured out some bits to pull piston pin, installed new bearings into piston then installed piston on rod. Had to use original pin as new one slides right in. Being all careful to get piston on right I got it wrong! Oh bother!
So pulling pin to switch it around
Fellas is there any OEM piston pins out there? What a cornball design somebody came up with eh!!
Continue on......
Now more ripping into the SP80
Edit
SP80 piston skirt measures 2.050" and bore measures 2.062"
Chainswr aftermarket piston measures 2.060" so much better for sure!
Figured out some bits to pull piston pin, installed new bearings into piston then installed piston on rod. Had to use original pin as new one slides right in. Being all careful to get piston on right I got it wrong! Oh bother!
So pulling pin to switch it around
Fellas is there any OEM piston pins out there? What a cornball design somebody came up with eh!!
Continue on......
Walter Glover
ArboristSite Guru
I need help with how to get the rings into the cylinder? Old ones had a lot less spring to them and gave no trouble
Is there some dimensions or tips wrt an entrance sleeve or sumsuch?
At wits end on that one
Edit:
Mark came through for me again! Thank you sir.
Ring grooves not deep enough for the rings on these Chainswr pistons. Took the Dremel after the inside surface and removed 0.005" from the two rings. Lightly emery tobreak sharp edges and the piston slid right in. Very pleased
Assembled engine to try to pressure test and flow check piston. Could not get a number as it now leaks past the rings. So going to run it and maybe the rings will break in.
Is there some dimensions or tips wrt an entrance sleeve or sumsuch?
At wits end on that one
Edit:
Mark came through for me again! Thank you sir.
Ring grooves not deep enough for the rings on these Chainswr pistons. Took the Dremel after the inside surface and removed 0.005" from the two rings. Lightly emery tobreak sharp edges and the piston slid right in. Very pleased
Assembled engine to try to pressure test and flow check piston. Could not get a number as it now leaks past the rings. So going to run it and maybe the rings will break in.
Walter Glover
ArboristSite Guru
Ring width reduced from 0.090" to 0.085"
ML12
ArboristSite Guru
^^ I had this exact same issue with my chainsawr piston. I also had to clearance the skirt because it smacked the counterweights on the crank.
Walter Glover
ArboristSite Guru
Sp80 is a runner!
All back together and now carb adjustments make sense. Idle stop screw is out about an eight of an inch from before. Mixture screws are pretty much 1 turn out.
Idles sweet and starts easy. Compression is pretty good considering the shape of the cylinder. Will try and get it into some wood this week to seat those rings
Thanks again to Mark and Tim your tips mean a lot!
Cheers
All back together and now carb adjustments make sense. Idle stop screw is out about an eight of an inch from before. Mixture screws are pretty much 1 turn out.
Idles sweet and starts easy. Compression is pretty good considering the shape of the cylinder. Will try and get it into some wood this week to seat those rings
Thanks again to Mark and Tim your tips mean a lot!
Cheers
Good to hear it Walter. When you cut with that I think you will be impressed.
Out cutting today. I had to top a tree so I could cut it dawn. I had the PM6 out with me to top the tree with and the PM610 to fell the tree after topping it. Love the PM6. Nice and lite up in a tree. Cuts great for a 32cc saw. Thanks Ron.
Brian
Brian
