McCulloch Chain Saws

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The best way to upgrade to a 70cc cylinder is to replace the short block so you keep the cylinder and crankcase together. The 54 and 57cc models did not use the bearing insert on the PTO side, the 60, 70, and 82cc models all used the insert in one form or another. To try and match a 54cc crankcase bottom/oil tank with a 60, 70, or 82cc cylinder would require some intricate modifications to the bearing insert to get the halves put together and sealed.

With so many of the 63258/84080 insulators out there, no need to make something up, just get the right insulator and gaskets.

Mark
 
Good information Mark. I'm trying to put a plan together before I dive in. A quick look on eBay didn't help much. Porting a basic 10-10 may make more since. It's a shame rechroming these old cylinders are so expensive.

Thanks. Jason.
 
Well it can be done.
Carb off an old beat up Stihl 051 can be fairly easily swapped out into a 125SP with a bit of parts swapping to keep most everything original in the Yellow saw and gain you two jet adjustment.

Old single adjustable carb with the swapped out bits added back into it.

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I pulled/swapped out the choke and throttle plates- and their rods from the original carb and placed them into the 051 carb- in an effort to keep all the linkage rods the dame. This does not work for the choke rod and the original is above- I had to make an inverted bend rod from a bicycle spoke.
I also swapped the top cover to allow for the upright nipple position that suited the 125 impulse line position better and pulled the larger fuel nipple from the single adjust carb to fit into the 051 carb.
The 051 also has a case mounted idle screw- so I had to drill and tap a suitable screw into the throttle stop, borrow the spring off the original and add it to the carb body- if I ever did it again I would pay more careful attention to the angle of the original- had to relieve some carb body material to allow the screw head to pass.

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New homemade choke rod installed- the sharp eyed will see the difference.



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No case relief necessary and both adjust screws are easily accessed from the original port.


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What I had handy in 3mm was used for an idle screw- the nut under the cap head is to hold the spring.


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Adjusters through port.


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Carb donor.


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I like it! Ive not been as active here as i used to be but ive put together some real frankenmac saws in the past. Mixing and matching parts is so much fun cause they take little to make it work. Well done on that carburetor.

Mark is correct there arent any 70cc cylinders that are bolt ons but an entire 70cc engine will fit right into all those parts. I still want a rigid 82cc mcculloch and i dont know why. It would likely vibrate so bad it would not be fun to operate. I guess just to say i did it. Maybe one day when work slows down i can get back into them again.
 
Keen as to see an 82cc 7-10 vinny. Power to weight would be unreal. Some good gloves for AV 🤣

Good Job Bob. Come up for a drive so I can have a turn on this thing:)

Be through on Wednesday- with a few banana boxes and fish bins full of Stihl parts, saws, bars etc.
 
Hi everyone I was wondering what a sp125 block new in the box would be worth im thinking of trading it for some other 125 parts but would like a little insite on what I should get outta it, I haven't searched for a nos one but would imagine they are slim to none thanks in advance
 
I know heimannm has a lot of McCulloch Chain Saws, as well as myself, I was wondering if anybody else has a few McCullochs in their collection of Chain Saws, and are they for work, or for display. Thanks for your input. Bruce.
I collect the McCullochs and they are for work and display, but not daily use in my book. I personally have to many to keep up with the maintenance. You have to use them to keep them running or eventually they won't run anymore and you gotta work on them, so I take out as many as I can when I want to make a little noise, but my go to saws for reliability are new Echos. My Macs were my go to saws, but I had to bring like 6 of them with me just in case I had problems and was kinda sick of working on them" I mean they are 40-50 years old". So now, yeah for nostalgia, and playing the beautiful music they make, I still use them for work because they are very enjoyable to run, but I haven't really taken the time to fully go through every nut and bolt on any of them to make one that is reliable enough and that is the reason for buying the new Echo saws that I have.
 
Them old macs have a lot of parts. You really need to be a mac specialist to work on some of them. I have a few of them ive been farting around with for a few years. My 1-70's compression is really high. Literally broke the starter in half pulling on it. Later discovered the points plunger was sticking. I'll put a chip in it I guess. The 10-10S will be the next project. I noticed a nos short block on ebay today for crazy money. 550 just needs bar plates, it runs great. Enough parts to make a couple more. All on the when I get around to it list.
 

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