Thanks Nick. I've had the ball and seat apart several time and all looks good. I'm wondering if I may have the metal orifice plate (47) on backwards or the idle mix screw is too far in. See attached - my plate has three large holes (I added the yellow one) and one very small one. I have it on the way it shows in the drawing. Hoping that correcting the idle mixture screw will correct it.
McCulloch Chain Saws
- Thread starter Bruce Hopf
- Start date
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Nickolas
Retired and messing around with old stuff...
From a bulletin they eventually did away with those original gaskets that had the screen in them along with that plate. It doesn't take much to clog the fine wire mesh in it and then another reason your saw won't run right. Lots of issues with these back in the day. There are several possibilities so it's a trial and error process.
These saws are all I mess with anymore but I mainly run a 4-30a and a 77. I've got those two running like a fine watch. I always tear them completely down and make new gaskets, replace seals , rebuild carb, fuel pump and then a nice leak free machine. They can be finicky at times but patience will pay off..
My favorite 3-25 two button saw. Runs in great shape but will never see wood for being too rare...
Sent from my 0PM92 using Tapatalk
Brian and I did a little cutting down at the wood lot with our 800s. I was going to have his son make a video of us cutting side by side on a 3 1/2" red oak - just wanted to finish bucking a 30" log first - then the 800 started making a vibrating hum. Shut it down to find the muffler and DSP valve off. The heat and vibrations destroyed my homemade aluminum spacer and broke the safety wire. Fortunately nothing appears to have been ingested though all of the spacer is not accounted for. I guess I'll have to buy the factory bolts and locking strap plus something to keep the DSP valve tight.
Ron
Ron
Cutting with the PM 800. Ron in the background with his PM 800.
Not a good picture took with my old flip phone.
Brian
Not a good picture took with my old flip phone.
Brian
I was watching National Lampoon's Christmas Vacation. I could not see that well but it looked like the chainsaw that Clark used to cut the tree down is a Mac 610.
Brian
Brian
And now................
https://www.ebay.com/p/Chainsaw-Cla...n-8-Clothed-Movie-Figure-NECA-2017/2194177046
https://www.ebay.com/p/Chainsaw-Cla...n-8-Clothed-Movie-Figure-NECA-2017/2194177046
Yep, Looks like a PM 610. Might be a must for Christmas.
I believe I found the problem. Everything is assembled correctly. The plate can only go on one way. See attached. I made a plate to replace the upper chamber of the carb so I could pressurize the diaphragm and it is leaking under the clip under pressure. If I lift up on it slightly it bleeds off VERY slowly but when I release it, it bleeds out quickly.
ChoppyChoppy
Tree Freak
250.
ChoppyChoppy
Tree Freak
ML12
ArboristSite Guru
Got my SP-81 back together, noticed that it has a weird version of the SDC carb in it (only one adjustment other than idle speed).
But it runs great and has enough compression that without the compression release I can barely turn it over.
But it runs great and has enough compression that without the compression release I can barely turn it over.
ML12
ArboristSite Guru
Also had some time to try and figure out a carburetion issue on another mac saw, the 1-72. Seems no matter what settings I had, fuel would just pour out the carb throat. I replaced the needle and seat and it had new diaphragms. So I gave up and swapped in a known good carburetor, only to experience a massive fuel leak from somewhere else in the carb box. whatever. I will fix it another day. Or order another Chinese HL carburetor to put on it.
Excuse the husky in on the bench, it was also getting some work done.
Excuse the husky in on the bench, it was also getting some work done.
My SP81 originally had that carb. It was used on serial numbers with prefixes 11 and 12 which also used a different tank. I messed up something (can't recall what) rebuilding the carb and decided to go with a fully adjustable one since I had a large venturi version available and also had to change the tank (thank you Mark) to accommodate the adjustment screws.
Still haven't gone back to it and figured out a timing issue, but like yours, it has unreal compression and I'm afraid of breaking the rope or starter pulling it over enough to get a good compression reading.
And that Husky is perfectly excusable.
Still haven't gone back to it and figured out a timing issue, but like yours, it has unreal compression and I'm afraid of breaking the rope or starter pulling it over enough to get a good compression reading.
And that Husky is perfectly excusable.
BigBlue
ArboristSite Operative
Is that 1-72 a giant sized saw or is it just the camera's perspective that makes it look so much larger than the 10-series sized saw to the right of it on the bench??
Rob
Rob
ML12
ArboristSite Guru
Its partly perspective and partly just a larger saw. The 1-72 is in a vise about 10" in front of the sp81. The older large frame saws are dimensionally pretty big compared to more modern saws.
Walter Glover
ArboristSite Guru
ML12, love your SP81! Fine looking saw there. Love those series 10 Macs. Look forward to seeing it in some big B.C. wood eh? Around here a 20" bar can handle anything that needs cutting.
HeRoze
Addicted to ArboristSite
Hey - I hope this isn't a foul, but if you know anyone that can travel to GA I'm getting rid of a lot of saws, mostly Macs
Link: Want to Sell - Instant CAD
Link: Want to Sell - Instant CAD
My BIL brought me another saw yesterday from his town transfer station.
1999??? Mac Timber Bear ?mod 60013414 SN11-059617-
?55.5cc? acres site is not clear about bore/stroke on this model-
20"-3/8-70dl- PHO 14lb15oz
sorry have not put a pix in my gallery yet. Not all beat up, looks clean
170psi...oily residue in tank, came with new tygon 4040 line from filter to carb. I then half filled with fresh mix. primed in carb and fired it, repeat 3 times. Finally ran on tank fuel... felt strong and as expected LOUD.
Ran it for 20-30 seconds and it never seemed to put any oil on the bar. Does it need a new oiler diaphragm? any corrections or suggestions about typical failure of oiler.
TIA
1999??? Mac Timber Bear ?mod 60013414 SN11-059617-
?55.5cc? acres site is not clear about bore/stroke on this model-
20"-3/8-70dl- PHO 14lb15oz
sorry have not put a pix in my gallery yet. Not all beat up, looks clean
170psi...oily residue in tank, came with new tygon 4040 line from filter to carb. I then half filled with fresh mix. primed in carb and fired it, repeat 3 times. Finally ran on tank fuel... felt strong and as expected LOUD.
Ran it for 20-30 seconds and it never seemed to put any oil on the bar. Does it need a new oiler diaphragm? any corrections or suggestions about typical failure of oiler.
TIA
Walter Glover
ArboristSite Guru
Pics would be great.
Oiler should be gear drive which can fail. Tabs on oiler gear are weak esp if thick summer oil used in winter.
I have a 4600 mac that the tabs are nearly gone so thinking that was the issue.
Oiler should be gear drive which can fail. Tabs on oiler gear are weak esp if thick summer oil used in winter.
I have a 4600 mac that the tabs are nearly gone so thinking that was the issue.
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