Stihl 048 rebuild

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Woodslasher

Make McCulloch Great Again!
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As some of you have seen in the "you suck" thread I bought a beat-to-crap 048 last Friday evening. By noon Saturday the carb was in the saw shop being cleaned and the saw was moderately disassembled on my bench. Early Disclaimer: Pictures until re-assembly are being withheld due to forgetfulness and shame over buying something with the hack-job CRAP that was done to it. I've ordered a boatload of misc small parts it needs and a crankcase from ebay so for now I am patiently waiting for the postal service to deliver them. In the meantime, yesterday I went in to a chiropractor for neck pains and popping and was told I have scoliosis. As part of the treatment I now have restrictions on neck movement and leaning over/hunching over work for an indefinite amount of time. Due to all that, this might be a slow build. Anyways, back to the saw, I checked the compression on it and it is approx. 120lbs dry. No oil or mix was involved, which, looking back on it, was a stupid thing to do. Is that # good, bad, or just usable?
 
It is always dodgy to give advice about 2 cycle engine running condition over the internet based on a compression reading. Pull the cylinder and check things out.

That era of saw tended to pass a lot of fine dust through the filter and would wear the intake side not to mention run rings until they were super thin and still start up and keep cutting. There is however a lot of difference in performance.

That being said, 048s are the overbuilt anvils of the Stihls. Okay power, take a beating that would park most saws. One of the saws that every collection should have.
 
Yeah, 120 sounds kind of low. Granddad, then dad, ran an 048 hard, but not to death on the farm. It had a tendency to suck a lot of fines behind the filter when I would go to clean it, worse, for some reason, than the 028 & 038 Mag they had.

That 048 is probably still running or in a barn somewhere out in Oldham county. Dad always ran it with a 28” bar, sometimes a 32. Beastly saw, not a high revver, but a real good saw for long bars, even in hardwood... That particular saw saw a lot of hedgeapple (Osage Orange for the non Kentuckians here) which were always fat at the stump. Stumping with that saw had a lot of fines.

In all it was a very modern saw for when it was introduced. A lot of the things pioneered on that saw made their way to the 038 Mag II then into the 044/064 range. The case design was the only weird part. It was very sturdy, but the fuel and oil tanks were right on top of each other near the handle. It probably didn’t help the case halves were only held together by four screws.
 
Turns out that the drill ran out of grunt at 120, so the saw probably has higher compression than I thought. Sometime soon I'll put an air impact on it instead of a cordless drill and re-check it.
 
why not just pull it over by hand? also be careful of the switch shaft. they have been NLA for ages and i think are the hardest part to come by for these.
 
Well, after lots of impatient waiting for the crankcase, it arrived yesterday! Then things went south. I won't go into details on how, but 1 (spare) crankcase half got busted, a piston arm got bent or was bent, the p and c turned out to be scored beyond repair (not by me), a bearing was blown to bits, and I need to order more parts and wait for them to arrive. I have to order a clutch side bearing seal, a crankcase gasket, clutch springs, and a piston and cylinder for either an 048 or I heard an 056 super II piston and cylinder will fit as well. Any thoughts on that?
 
Well, all the raised crap on the cylinder came off with a little help from some acid so I won't need a new one (I hope) but now I'm wondering, what is transfer? Is it just the raised crap or is it the shiny spots? I'm hoping its the former as 70-80% of the cylinder walls are shiny. Also, where can I get clutch springs for this? One broke in half (not through my abusing it) while I was popping the clutch off so I need new ones. Here's some pics of the areas in question on the cylinder after cleaning. It's not quite done yet as I'm still tracking down and cleaning up the last few nail-catchers. The first pic is the cleaned up area and the second is of the shiny spots.
IMG_3407.jpeg IMG_3404.jpeg
 
I've used a split mandrel with emery cloth to clean up transfer, then I have special home made "hone" to clean them up. (eye bolt and scotchbrite)
There is a good video on youtube of one of the members here cleaning up transfer. Just go slow.

From your photos I'd say that looks salvageable.

When re-assembling or stripping down a saw, heat is your friend, a lot of the castings are delicate and using differential expansion is a good way to make things come apart or go together easily.
 
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