McCulloch Chain Saws

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Well the 10-10s has me stumped. At this point I think the carb is bad. I rebuilt it. Even changed out the Welch plugs. Held vacuum good. Put it on saw it popped once then flooded. Gas coming out exhaust now. Gas in carb.Pulled plug cleared it. Flooded again. That was last night. Pulled carb this am checked needle value assembly and Welch plugs. Put it back together. Got it cracked and never got a screw driver on it and it died. Flooded and gas everywhere. Going to pull another carb off a parts saw and rebuild it. It’s a test of wills now. I am gonna figure this out lol

If the 2nd Carb you put on presents the same results, the problem may be the coil. I had a similar issue with a 10-10S I put together. Spark was actually blue and looked strong when I tested it, but it kept flooding and would not run. I swapped out the coil with a NOS one I found on eBay and the problem was fixed! She runs like an absolute top now.
 
Is the needle lever set level with carb body? Did you put the tit on diaphragm into slot in lever? If you don't it can push down on lever and hold needle open.

I know these are kinda obvious things but good things to double check.
Yes Sir on both counts. Even opened back up to triple check it and the Welch plugs. I will figure it out at some point. Never had a carb give me this much trouble before. It’s personal now lol.
 
If the 2nd Carb you put on presents the same results, the problem may be the coil. I had a similar issue with a 10-10S I put together. Spark was actually blue and looked strong when I tested it, but it kept flooding and would not run. I swapped out the coil with a NOS one I found on eBay and the problem was fixed! She runs like an absolute top now.
Thanks! I will check that if carb two acts the same way. I have 4 other 10-10s parts saws so I may grab a coil and try that first
 
Scratch my last post.

With some tedious use of a tap & die, I fixed the threads on the flywheel nut and the crankshaft! Goes on good now.

Now that I got the ball rolling, any recommendations on a flywheel puller for an SP125?
 
Hey Roland how did you get that duration? You were talking about shaving the piston skirt a while back
Jethro,

I set the timing to where I wanted it and scribed a line on the piston skirt, then pulled the crankshaft assembly out the block. Luckily I have a toolroom to hand so I quickly milled the material off the piston skirt to the line, but could have easily filed it if needed. A small chamfer filed on the new edge allows smooth progress over the port, and also may help keep up oil film thickness . Amount of metal removed around 1/8" or so. I did not strip the rod off the crank but made very sure all swarf was cleaned out of the bearings. Low hour saw, all was tight and found no reason go further into the rotating assembly.

Hope this helps - Roland.
 
Here I thought MACs ran on regular gas mixed with non-detergent 30w motor oil with used oil for the chain because that is how Dad did it. Read the owners manual when I got my 700 and began mixing with two stroke oil. Years later switched the chain to bar oil.

Ron
Haha, sounds like me when I got into old cars. I must've gotten volumes of misinformation and myths that had been passed down over generations, I finally started collecting Chilton books and talking to manufacturers about how things were supposed to work.
It was more effort to learn that way but honestly the results were better, and I always ran anything experimental to see if a theory was accurate.
 
Aaron - I took a large, round, heavy washer and drilled two holes to align with the 1/4-20 tapped holes in the flywheel (circled in red below). I use a couple of socket head cap screws to affix the washer to the flywheel and use my two jaw gear puller to grab the washer. It is a good idea to back off the flywheel nut but leave it on the crankshaft to prevent the flywheel from becoming an identified flying object when it pops off. Some times if they are really stubborn you still have to put a lot of tension on the puller and give it a sharp rap with a hammer to break it loose.

DSCN0456.1.jpg

For future reference, the 7/16-20 flange nut will work but I normally use a jam nut since clearance for the starter can be an issue on some saws.

Mark
 
Even changed
Here I thought MACs ran on regular gas mixed with non-detergent 30w motor oil with used oil for the chain because that is how Dad did it. Read the owners manual when I got my 700 and began mixing with two stroke oil. Years later switched the chain to bar oil.

Ron
I still get them to repair all the time with old used motor oil as chain oil.

Brian
 
Alright fellow Mac fans. I'm getting the sp81 back together. I have the reed style muffler that was on the saw and a louvered muffler that was on my sp80 parts saw. Stick with the reed muffler or does the other perform better? Or maybe no noticeble difference either way?20200613_205748.jpg20200613_210111.jpg

Got my Timken seals installed on crank all ready to go.20200612_214742.jpg
 
As I sit in an imaginary circle, I turn to folks not there and say, "I am a packrat. Though I can do something with that I will throw it away before I go under. Although I will never be highly organized or disciplined like many MACnuts, I will take inspiration from them and clear my house."

I returned late Friday night from a vacation of doing nothing except eat and sleep. Well, there was that 8000 step barefoot death march just before the 620 mile return trip. Good thing my wife didn't think of it earlier as I can just now step on my blistered foot.

With limited mobility, I decided to continue my slow cleanup of the basement and the chainsaw lab. I have so much junk it is hard to navigate. Every kind of container imaginable full of screws, plumbing bits and pieces, wire, other misc. hardware, lumber stock and scrap, aluminum stock and scrap, steel stock and scrap, tractor parts, saw parts, truck parts, fluids of every sort, paint, household stuff, the list goes on and on, and that doesn't count my tools and cool stuff.

I am a packrat. Even though I can do something with almost anything, I must throw it away before I go under. There I said it to real people. To MACnuts no less.

Now for the big divide - keep and don't keep. Don't keep means trash it, scrap it, sell it or give it away. Trash should be the big winner as only another afflicted person would want most of what I have kept.

One "benefit" of being disorganized is finding stuff you had forgotten. In a filthy box I found two NOS old style 82cc exhaust ducts and one each of the two different spark arrestor screens. Reminded me that no doubt the big mufflered PM800 makes more hp than its predecessor in stock form as its screen probably flows twice what the old screens would flow.

If I find some MAC stuff that needs to go and that Brian doesn't want, I will post it. Don't hold your breath in anticipation as MAC stuff is only a small fraction of my horde.

Ron
 
As I sit in an imaginary circle, I turn to folks not there and say, "I am a packrat. Though I can do something with that I will throw it away before I go under. Although I will never be highly organized or disciplined like many MACnuts, I will take inspiration from them and clear my house."

I returned late Friday night from a vacation of doing nothing except eat and sleep. Well, there was that 8000 step barefoot death march just before the 620 mile return trip. Good thing my wife didn't think of it earlier as I can just now step on my blistered foot.

With limited mobility, I decided to continue my slow cleanup of the basement and the chainsaw lab. I have so much junk it is hard to navigate. Every kind of container imaginable full of screws, plumbing bits and pieces, wire, other misc. hardware, lumber stock and scrap, aluminum stock and scrap, steel stock and scrap, tractor parts, saw parts, truck parts, fluids of every sort, paint, household stuff, the list goes on and on, and that doesn't count my tools and cool stuff.

I am a packrat. Even though I can do something with almost anything, I must throw it away before I go under. There I said it to real people. To MACnuts no less.

Now for the big divide - keep and don't keep. Don't keep means trash it, scrap it, sell it or give it away. Trash should be the big winner as only another afflicted person would want most of what I have kept.

One "benefit" of being disorganized is finding stuff you had forgotten. In a filthy box I found two NOS old style 82cc exhaust ducts and one each of the two different spark arrestor screens. Reminded me that no doubt the big mufflered PM800 makes more hp than its predecessor in stock form as its screen probably flows twice what the old screens would flow.

If I find some MAC stuff that needs to go and that Brian doesn't want, I will post it. Don't hold your breath in anticipation as MAC stuff is only a small fraction of my horde.

Ron

Haha I have a storage 8x12 in another state! Full of old rare car and truck parts, before the storage I filled a dumpster 3xs with just junk stuff. At some point I realized that I wasn't gonna live long enough to play with it all.
With the chainsaws though they are smaller and less expensive then street rods , but you'll notice that from time to time I'll ship rare" Mac "stuff I'll never used to the man with the museum .
Any more I'll check to see if someone wants to trade stuff or just wants it and I'll mail it out.
The way I find stuff is better then most ,so its more of a problem of finding too much of whatever , I have to narrow the focus alot and decide what I'll really have fun with. McCulloch saws are fun to me ,they run great and sound like a hot rod , I know there's probably better saws (new) out there but I feel like I'm wasting my time if its no fun cutting , or worse WORK. If its old and loud I probably will like it.
 
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