McCulloch Chain Saws

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Yukon Stihl

Yukon Stihl

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I didn't thnk the damage inside the crankcase was too bad so I cleaned everything up began reassembly. I like to pressure test before moving on and after several failed attempts (I had the block off for the intake upside down...) I realized there was a leak somewhere...

I had to resort to dunking it in water and found the problems, at some point when the crankshaft pinched the BB against the side of the case it distorted it and cracked through. The ones in the green circle were O.K. but the one in red...

View attachment 1058554

...led to this.

View attachment 1058555

I cleaned it very thoroughly and applied some JB Weld to the interior surface. I learned from Terry Ives that warming everything up first helps the JB flow out. I'll do a little grinding, filing, sanding to clean it up before putting it back together.

View attachment 1058556

Mark
Right there shows the value of a vac and pressure test.
 
knightmax

knightmax

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I didn't thnk the damage inside the crankcase was too bad so I cleaned everything up began reassembly. I like to pressure test before moving on and after several failed attempts (I had the block off for the intake upside down...) I realized there was a leak somewhere...

I had to resort to dunking it in water and found the problems, at some point when the crankshaft pinched the BB against the side of the case it distorted it and cracked through. The ones in the green circle were O.K. but the one in red...

View attachment 1058554

...led to this.

View attachment 1058555

I cleaned it very thoroughly and applied some JB Weld to the interior surface. I learned from Terry Ives that warming everything up first helps the JB flow out. I'll do a little grinding, filing, sanding to clean it up before putting it back together.

View attachment 1058556

Mark
hope she holds Mark!
 
bob kern

bob kern

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yodayoda

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I’ve got a PM 700 I got from my Dad a few years ago I’m trying to get going, currently have a coil coming from knightmax.
Another thing I’m trying to figure out is the decompression, the passage in the head seems to be plugged. I’ve got the little Allen screw out on the head and can’t get any air or carb cleaner through it. Any suggestions?
Thanks Roy
 
yodayoda

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Best option might be to drill it out. Little at a time and upside down so the carbon doesnt fall into the engine. Carbon is very hard and has ruined many of the chrome on these saws. Make provisions somehow of not getting carbon into the engine.
Thanks, I took a small drill bit and clamped it a vise grip and slowly worked it and alternately blew out the pieces of carbon with compressed air after every couple turns,I would never have thought carbon would be that hard
 
knightmax

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Thanks, I took a small drill bit and clamped it a vise grip and slowly worked it and alternately blew out the pieces of carbon with compressed air after every couple turns,I would never have thought carbon would be that hard
FYI... You should do that every year on a Mac with a decomp clean out that you run alot. It will save the cylinder chrome.
 
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