McCulloch Chain Saws

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I'll bet those holes were a try for oil retention. I have an old IEL HC saw that has a piston with cross hatches knurled into it which we suspect was for the same reason.

Just guessing.

oem? have knurled tired pistons to tighten em up in bore [bikes w/iron sleeve], asked once upon a time if this was a good idea on saws w/o sleeves.
 
I have a Mcculloch pro Mac 700 that I cannot get to hold pressure or vacuum and I've tried everything. I've asked here several times. I've sprayed down the whole saw with soapy water and cannot find the leak. I checked around the oil pump and there are no bubbles there. I've tried using a rubber strip to seal the muffler with the gasket installed and I've tried a thick piece of rubber cut the size of the gasket with no luck. The crank seals are new and the saw has been taken apart and sealed with motoseal. Even around the bearings has a thin layer. What can I do? I can't find the leak and I've been trying for days?
Thanks


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I have a Mcculloch pro Mac 700 that I cannot get to hold pressure or vacuum and I've tried everything. I've asked here several times. I've sprayed down the whole saw with soapy water and cannot find the leak. I checked around the oil pump and there are no bubbles there. I've tried using a rubber strip to seal the muffler with the gasket installed and I've tried a thick piece of rubber cut the size of the gasket with no luck. The crank seals are new and the saw has been taken apart and sealed with motoseal. Even around the bearings has a thin layer. What can I do? I can't find the leak and I've been trying for days?
Thanks


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Did you try removing the decomp valve and sealing the hole up? They quite often leak some. I can't remember what the thread size and pitch is. If you can figure that out you can use a short bolt and gasket.
 
Depending where your testing, don't forget the plug threads as a leak source. Also don't forget to test your test setup itself. And yep, if all else fails, dunk it, but pressurize it first with constant pressure in the 8~10psi vicinity to keep the water from getting where you don't want it to go. Matter of fact, if you rig up a compressor and dial it down, you should be able to just hear the type of leak you're describing.
 
Did you try removing the decomp valve and sealing the hole up? They quite often leak some. I can't remember what the thread size and pitch is. If you can figure that out you can use a short bolt and gasket.

I have the compression release plugged with a bolt and some teflon tape. And the cleanout hole is plugged.

I've thought about dunking it in water, I just would hate to get some inside and rust up my bearings.


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The only thing I didn't check was the hose on my block off plate. I can try putting a screw clamp on the hose.


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Depending where your testing, don't forget the plug threads as a leak source. Also don't forget to test your test setup itself. And yep, if all else fails, dunk it, but pressurize it first with constant pressure in the 8~10psi vicinity to keep the water from getting where you don't want it to go. Matter of fact, if you rig up a compressor and dial it down, you should be able to just hear the type of leak you're describing.

I checked my testing setup at the gasket but I didn't check the hose to see if it was leaking.


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I have the compression release plugged with a bolt and some teflon tape. And the cleanout hole is plugged.

I've thought about dunking it in water, I just would hate to get some inside and rust up my bearings.


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Strip it to just the crankcase, pull all non essential parts like clutch, flywheel, coil, carb, the use pressure set at around 8 lbs. dunk it like mentioned earlier, then blow it dry, guaranteed to find the leak.
 
I have dunked one but it was stripped down to just the block which is where I perform my first pressure test. By the way it was the hose on my test setup that was leaking. As long as you keep it pressurized no water will get into areas that it will hurt. Just blow dry after you get it out. Also spraying down with WD40 after you dunk it is a good idea. Also these saws will take a lot of water on the external areas without harming them. Mix you up plenty of dish soap and water in a spray bottle and give it heck. (Heavy on the soap) On the external areas it will not hurt to get wet. I take it that you have the carb off and the points and flywheel off, muffler and also the clutch off. Get it down to that and lay the soap and water to it. As long as you have pressure applied it cannot get into the internal areas of the saw and the external is mostly aluminium. If you do get water inside of it spray it down with WD40, it will be OK.
Brian
 
I switched out my 8 pin .375 for a 7 pin .404 today and took it for a test run. The X brand 25” bar adds about 1 ½” over the MAC 24” bar.

My .404 7 pin setup actually pulls better than the .375 8 pin but I had a lot of bar vibrations at times. I don’t know if that is the .404 or the semi-chisel or something unique to the new chain or bar. Starting a bore seems to be easier with the wide nose. It is more difficult to change the .404 chain but the original goal was fewer changes. Test results were good enough to warrant field trials. We will see.

Ron

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I switched out my 8 pin .375 for a 7 pin .404 today and took it for a test run. The X brand 25” bar adds about 1 ½” over the MAC 24” bar.

My .404 7 pin setup actually pulls better than the .375 8 pin but I had a lot of bar vibrations at times. I don’t know if that is the .404 or the semi-chisel or something unique to the new chain or bar. Starting a bore seems to be easier with the wide nose. It is more difficult to change the .404 chain but the original goal was fewer changes. Test results were good enough to warrant field trials. We will see.

Ron

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Gasp! Brand x bars on brand y saws....... what is the world coming to?!
 

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