homelitejim
Full of Scrap
Thank you. I picked up another one today with a 770D for free.
McCulloch Chain Saws
- Thread starter Bruce Hopf
- Start date
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briantutt
Addicted to ArboristSite
That's why I said that. Looks like you had to sorta "catch" it when it fell through!
Eccentric
Mister Wizard
Good deal. I didn't mean to say the saw was slow.........just that it's not going to be hampered by cutting bigger wood. Between the gear reduction and the torque of that old beast, it'll eat a lot more wood without slowing down.
Good for you! That's quite a score. I'm trying to get a 770G from a local guy too. It won't be free though I'm sure....
homelitejim
Full of Scrap
I meant to throw a larger round in there. I have two waiting on the trailer, just too lazy before the video.Good deal. I didn't mean to say the saw was slow.........just that it's not going to be hampered by cutting bigger wood. Between the gear reduction and the torque of that old beast, it'll eat a lot more wood without slowing down.
Good for you! That's quite a score. I'm trying to get a 770G from a local guy too. It won't be free though I'm sure....
I was hopeing that the 770 was a G but it turns out it is a D. Looks like I can put a 3/8 sprocket and bar on it, just have to find one.
promac850
formerly promac610
It makes you admire the guys that had to use one of these on a day-to-day basis at work, doesn't it?
Hell of a workout, Acres lists it at 26 pounds, powerhead only. :jawdrop:
Eccentric
Mister Wizard
The 770D will take the same clutch drums as the C-series saws. I take it your saw has a 7/16" spur sprocket right now? The sadly out of production Oregon rim-drive drum (which'd let you run whatever pitch you want) is 10616. I don't have a spare to part with. They're always around on feebay. I bet Chainsawr has a few. I may have an extra .404 spur sprocket I could send you if you need it. I'm sure many other guys here do too. I suggest you run .404 chain on that beast. It's around 5.8ci/95cc after all. It'd be plenty fast with .404 RC...
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1375619cm3
ArboristSite Operative
Grandpa's McCulloch 1-51
Hi there im cody and sorry to pop in, i was wondering if anyone one here knew any info on the Mac 1-51. it was my grandpa's he bought new in '61. i received it about 6-9 months a go and would like to hear the old girl run again.
my email is
[email protected] if this doesnt belong here.
Hi there im cody and sorry to pop in, i was wondering if anyone one here knew any info on the Mac 1-51. it was my grandpa's he bought new in '61. i received it about 6-9 months a go and would like to hear the old girl run again.
my email is
[email protected] if this doesnt belong here.
homelitejim
Full of Scrap
1375619cm3
ArboristSite Operative
mac 1-51
thank you that helps out a lot does anyone have ipl for this saw im trying to get her up and running again. its been 20 years since dad accidentally broke it.
thank you that helps out a lot does anyone have ipl for this saw im trying to get her up and running again. its been 20 years since dad accidentally broke it.
I can send an IPL, I'll use the e-mail address posted above. If you are looking for advice and can put up with a little bull....you will find all kinds of help here.
Mark
Mark
1375619cm3
ArboristSite Operative
Mac 1-51
thanks Mark im sure there will be more questions to come.
thanks Mark im sure there will be more questions to come.
Tillotson HS vs Walbro SDC
I did in fact have an SDC18 on the CP70 but making the swap was a little bit more involved than unbolting one and bolting the other in place. Even though the CP70 has a remote impulse line, it is ducted to the mounting flange rather than having an outside connection. I did have another SDC carburetor so I took the cover off the fuel pump section and added a nipple I pulled from a spare carburetor from a 600 Series McCulloch. I thought I drilled the hole a few thousandths smaller than the diameter of the nipple but it ended up a slip fit. To lock it in place and seal it, I simply cut tube flush with the body of the carburetor and used a center punch to swage it in place.
To connect throttle linkage, I had to drill a hole in the arm (surprisingly hard material) and modify the tabs on the arm but with the drill press and a cut off saw and die grinder the job went quite nicely.
The choke linkage did not work at all, so for the test I simply removed the cover and air filter to flip the choke on to start it, then off once it was running. There was no idle speed adjustment on this carburetor (on the original the adjustment screw is in the air box) but the linkage stopped in exactly the right spot so the saw would idle low enough to keep the chain from turning.
The two saw, CP70 on the left, SP125 on the right
The CP70 flange, note the impulse port
The original set up on the SP125
There are many variations of the SDC carburetor, SDC18 (big bore) on top, SDC2 (small bore) below.
The SDC18 with the modified top and arm in place
Mark
I did in fact have an SDC18 on the CP70 but making the swap was a little bit more involved than unbolting one and bolting the other in place. Even though the CP70 has a remote impulse line, it is ducted to the mounting flange rather than having an outside connection. I did have another SDC carburetor so I took the cover off the fuel pump section and added a nipple I pulled from a spare carburetor from a 600 Series McCulloch. I thought I drilled the hole a few thousandths smaller than the diameter of the nipple but it ended up a slip fit. To lock it in place and seal it, I simply cut tube flush with the body of the carburetor and used a center punch to swage it in place.
To connect throttle linkage, I had to drill a hole in the arm (surprisingly hard material) and modify the tabs on the arm but with the drill press and a cut off saw and die grinder the job went quite nicely.
The choke linkage did not work at all, so for the test I simply removed the cover and air filter to flip the choke on to start it, then off once it was running. There was no idle speed adjustment on this carburetor (on the original the adjustment screw is in the air box) but the linkage stopped in exactly the right spot so the saw would idle low enough to keep the chain from turning.
The two saw, CP70 on the left, SP125 on the right
The CP70 flange, note the impulse port
The original set up on the SP125
There are many variations of the SDC carburetor, SDC18 (big bore) on top, SDC2 (small bore) below.
The SDC18 with the modified top and arm in place
Mark
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1375619cm3
ArboristSite Operative
mac 1-51 starter recoil spring
does anyone know how to disassembly the starter to get to the recoil spring. i was trying to start it and all of a sudden when i pulled it i felt something and now it will not retract. i assume that the ratchet is threaded on and has left hand threads, is this correct? and what i the easiest way to open it up. also what spring can i replace it with if it is indeed broken or is it possibly repairable with the old spring?
thanks for any ideas and all the help.
Thanks again mark for the 1-50 and 1-52 ipl.
i assume they are very similar. i know the handle off from the 1-50 is differant but modifiable to fit. (bought one and installed it)
does anyone know how to disassembly the starter to get to the recoil spring. i was trying to start it and all of a sudden when i pulled it i felt something and now it will not retract. i assume that the ratchet is threaded on and has left hand threads, is this correct? and what i the easiest way to open it up. also what spring can i replace it with if it is indeed broken or is it possibly repairable with the old spring?
thanks for any ideas and all the help.
Thanks again mark for the 1-50 and 1-52 ipl.
i assume they are very similar. i know the handle off from the 1-50 is differant but modifiable to fit. (bought one and installed it)
With the stock carburetor (.687 venturi and fixed high jet) my saw tops out around 10,000-10,500 out of the cut, definitely four strokes. With the SDC in place and adjusted a bit I could hit 11,300 RPM and still some 4 stroke. When we got to the woods to test it, I did richen the SDC about 1/8-1/4 turn as it was obviously lean in the cut.
In the woods today - to try and keep it even I put 36" hard nose bars on each saw, and new off the reel chains. Unfortunately the bars were differents (one .058 and one .063) though both are Carlton chisel.
You could definitely tell that the one with the SDC/adjustable carburetor would rev higer in the cut, yet seemed to pull as hard and keep going. This is the stock saw
Mitch thought the modded saw pulled better too
If all goes well, I will switch them around and try it again next weekend to make sure it's the carburetor making the difference and not the saw/bar/chain. I did recheck compression on each when we got back today and the SDC equipped saw was right at 150 PSI, the stock carb saw about 155 PSI. I would not have thought that a slight change in the venturi size and adjustable jet would make so much difference, at this point I am thinking it really does. In the end, I will probably keep one stock for those days I need to run a few tanks of fuel through making firewood, and keep the other for GTG's and such.
Mark
In the woods today - to try and keep it even I put 36" hard nose bars on each saw, and new off the reel chains. Unfortunately the bars were differents (one .058 and one .063) though both are Carlton chisel.
You could definitely tell that the one with the SDC/adjustable carburetor would rev higer in the cut, yet seemed to pull as hard and keep going. This is the stock saw
Mitch thought the modded saw pulled better too
If all goes well, I will switch them around and try it again next weekend to make sure it's the carburetor making the difference and not the saw/bar/chain. I did recheck compression on each when we got back today and the SDC equipped saw was right at 150 PSI, the stock carb saw about 155 PSI. I would not have thought that a slight change in the venturi size and adjustable jet would make so much difference, at this point I am thinking it really does. In the end, I will probably keep one stock for those days I need to run a few tanks of fuel through making firewood, and keep the other for GTG's and such.
Mark
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Brian, It's hard to say which has more power.
I have a few great running 797's and Supers.
The only real difference is you have less issues
with the SDC or Tilly HL set ups over the flatback
carbs.
Maybe this spring i will try to do a comparision.
Lee
Mark, I look forward to round two. I would have guessed that a carb off a 70cc saw would have been too small for a 125. I have looked, but have not found an interchange chart. Since the CP125 came with one of two fully adjustible carbs, I thought I would have a better chance locating one but not so. I don't know the Tiily's model number; just the Mac part number. That's one of the reasons why I started looking for an interchange chart. Surely one existed at some time in the past.
Thanks for all your work or should I say fun. Ron
Thanks for all your work or should I say fun. Ron
137, part number for the spring is in your IPL's, that same spring is used on many, many models so there are lots of them out there. I have been known to reform a broken hook on the spring by heating the end of the spring and bending it is pliers.
I like to rewind the spring into the starter housing, then slip the pulley in and get them hooked up. Others will suggest it is better to wind the spring up and grab it with long nose pliers and put it in the housing. For other saws with a deeper starter housing I do it that way as well, for one like yours I like to wind it in. Since I work on a lot of these kinds of saws, I have made the claim I can rewind a spring with my eyes closed (once it is started) and have done it in my shop just to prove to myself that I could.
Here I am giving a lesson in rewinding the spring at a GTG a couple of years ago, note the torch on the table already used to heat the end of the spring to allow me to reform the hook.
Mark
I like to rewind the spring into the starter housing, then slip the pulley in and get them hooked up. Others will suggest it is better to wind the spring up and grab it with long nose pliers and put it in the housing. For other saws with a deeper starter housing I do it that way as well, for one like yours I like to wind it in. Since I work on a lot of these kinds of saws, I have made the claim I can rewind a spring with my eyes closed (once it is started) and have done it in my shop just to prove to myself that I could.
Here I am giving a lesson in rewinding the spring at a GTG a couple of years ago, note the torch on the table already used to heat the end of the spring to allow me to reform the hook.
Mark
I was looking through the McCulloch carburetor book (PM me with your e-mail if you don't have a copy) and found several different saws that used the SDC carburetors with the bigger venturi, including a Super 2-10A which is a 54 cc saw!
I will now be looking for more of the larger SDC carburetors, as well as the Tillotson version. Somewhere I have a note from Hoss with the model # of the adjustable Tillotson, when I find it I'll send you a PM, don't want everybody out there snapping them all up...
Mark
As always thanks, Mark. Ron
igpoe
Addicted to ArboristSite
gob of work
Yep, gotta give it to ya................you don't mind putting in a whole bunch of work to advance the collective knowlege of the Mac boys. Nice pics too.
Many will wanna switch I suppose, making the carbs even harder to find, but I guess that's a wash since it is US that has them! I hope the fellas will remember to make sure they're rich enough when they initially crank them after switching. And if there's any (like myself) who don't have a good ear for the four-stroking, get someone who does,(like Stinkbait) to do the final tuning 'cuz the
SP 125s of the world must NOT be burned-up!
Igpoe
Yep, gotta give it to ya................you don't mind putting in a whole bunch of work to advance the collective knowlege of the Mac boys. Nice pics too.
Many will wanna switch I suppose, making the carbs even harder to find, but I guess that's a wash since it is US that has them! I hope the fellas will remember to make sure they're rich enough when they initially crank them after switching. And if there's any (like myself) who don't have a good ear for the four-stroking, get someone who does,(like Stinkbait) to do the final tuning 'cuz the
SP 125s of the world must NOT be burned-up!
Igpoe
