McCulloch Chain Saws

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I set my points from .015 to .017 on those large Mac's.

That was the initial setting from the factory, however they changed it to .016 on the karts and big saws. It was posted in a service bulletin, I was just looking at it, so I'm absolutely positive of the info.

Eric

I tried .020. it had starting issues, though I don't remember exactly what they were, and was recommended to close it up. I did and it worked for me.

Thanks for the great info guys. I will re gap the points and see what that does before I touch the carb.
 
I have them set at .016 now. I didn't try it yet as it was Canada day today. Heading to the fireworks in a bit

It was kicking back some but with the decomp it was OK. As it slowed to a stop when stalling it kicked back so hard. It pulled the starter handle shaft almost all the way into the starter. Still may have a carb issue. I'll find out tomorrow. I would feel pretty lucky if I don't.
 
It's so warm here I decided to pull the welch plugs on the carb and there was crap in the the idle orifice pit and a couple were plugged.

The last thing at this point to fix is the fuel cap check valve (new) which is not seating. I think the sintered plug is just vibrating up and the valve is losing it's seal.

Thinking on that one.

Here a little garage rev.
Thanks all for the helpful input.

 
Where did you end up on the ignition issue?

I set the points at a safe .016" I'll leave it there until I can try a cut with the saw to see how it performs under load. That at least stopped the violent kick back at stall or switch off.

I got to thinking (as I rarely do) and I have not a had an issue with a saw with a slightly advanced ignition starting or running well. They can kick back some though.
Since it's so darn warm here I decided to pop the welch plugs and see what the check valve screen and idle port chamber looked like.
Crap in the idle port well and two blocked ports. I did the carb in a cup of seafoam sitting in the USC full of water. Ran a few 6 minute cycles and then one with soap and water and one water only.

I believe it was all carb issue.

This saw is nice to work on (so far anyway) as it's big and there's lots of room around everything. A well thought out saw with lots of captive nuts and hex pockets for starter cover nuts. Common stuff that gets stripped out by the heavy handed.
Compared to an SP80 or 81 it's a piece of cake.
 
This saw is nice to work on (so far anyway) as it's big and there's lots of room around everything. A well thought out saw with lots of captive nuts and hex pockets for starter cover nuts. Common stuff that gets stripped out by the heavy handed.
Compared to an SP80 or 81 it's a piece of cake.

I'd love to give one a try!
 
We're you able to confirm the timing on that 125 Tim?

I didn't try Walter. The spec they show in the piece of repair manual I have is 26 deg BTDC. At some point I should calculate what .001" in point gap change is in degrees in timing I try not to get the old saws.



Snappy acceleration Tim, the CP/SP models all seem to have a little something extra in that regard.

Mark

They sure do!
 
Here's hoping one drops in your lap as well!

Well, I certainly can't complain about the good fortune thus far when it comes to my little Mac collection. Anything else falling into my lap would have me looking over my shoulder for a lightning bolt!

....imo timing with an ohm meter is what your engine needs

I generally understand the concept, but would you explain your particular method in detail, please?
 
Using an ohm meter or continuity tester, with the condenser disconnected you can detect exactly when the points open. With a degree wheel properly adjusted, you can read directly the amount of advance when the point open as you rotate the flywheel direction; McCulloch always specified 26º BTDC. Knowing all that, I still set them around 0.018-0.020" and call it good enough...

Mark
 
Pogo
I use a cd marked in 10 degree grads with a sharpie or a copper wire twisted around the shaft and then mark tdc and timing from there. Find top dead with a piston stop. Piece of 1/8" solder works great. Set wire or degree wheel tdc such that both stop points are equally spaced each side tdc. Once that is set with DVM across points to ground i set the points to open at timing mark as specified. Once you do it a couple times i find it easier than a feeler guage. Also you want to see zero ohms when points close.
 
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