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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.
McCulloch Chain Saws
- Thread starter Bruce Hopf
- Start date
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Thanks for the great info guys. I will re gap the points and see what that does before I touch the carb.
Super 797 for sale. https://www.arboristsite.com/community/threads/testing-waters.322380/#post-6609200
Ron
Ron
I always set the points around 0.018-0.019", makes it somewhat easier on the fingers when starting a big saw.
Mark
Mark
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 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.
Walter Glover
ArboristSite Guru
I set a gap then fine tune based on 30 degrees opening of points. Ohms scale with condenser disconnected
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.
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.
I'd love to give one a try!
Here's hoping one drops in your lap as well!
Walter Glover
ArboristSite Guru
We're you able to confirm the timing on that 125 Tim?
Snappy acceleration Tim, the CP/SP models all seem to have a little something extra in that regard.
Mark
Mark
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.
They sure do!
Walter Glover
ArboristSite Guru
Tim, imo timing with an ohm meter is what your engine needs
I have been going on the point gap alone for 10 years or so, seems to be working well for me.
Mark
Mark
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!
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
Mark
Walter Glover
ArboristSite Guru
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.
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.
