McCulloch Chain Saws

[MacAttack]

I guess my points need some attention....thoughts? Source of my weak spark?

 

[vinnywv]

Cleaning them yes. They arent horrible but pitted. Clean them up anf that will help. With electircity in any form....clean everything. All points of contact with every terminal. Clean off where the coil mounts to the engine so you have a good ground. Clean every spot that any electrical part touches anything. Without good clean contacts electricity can weaken. Also maybe think about the condenser. That helps store the spark. It could be a hinderence also. Power chips such as nova II chips or others can help diagnose problems. They take the place of points and condenser. I will often temporarily put one on a saw to test the points and condenser. If i have the hot white spark with a chip and a orange or less white spark without then likely the points or condenser are the culprit. I do have several saws that run with a chip all the time and others i keep the points. But clean every contact and try again.

 

[cbfarmall]

Depending on how the points come apart, I clamp them in a vice and hit them with a chain raker flat file, then polish with ultra fine sandpaper, degrease and wipe with a dollar bill. Both sides.

I found on my S250, which uses the same ignition, they get real touchy if the gap is too wide. And by touchy, I mean they don't spark. Double and triple check the gap after you tighten.

 

[matt_lamb_160]

Check the condenser. The coils on these saws are very reliable and the points are pretty robust.

 

[Rocker59]

I was taught to take a strip of 1000 grit sand paper and fold it over. With the points assembled, put the sand paper between the points and pull it slowly through the points, keeping pressure on assy to keep it closed. This way, if the contacts are not flat to the assy, they are parallel to each other.

 

[MacAttack]

Not perfect....but a LOT better.

 

[MacAttack]

Thanks for all the ideas!

I do have a Fluke meter that measures capacitance, I'm going to try and get a reading on the condenser.

 

[Joe Crow]

I used Mark's method to clean the points and the saw fired right up

 

[MacAttack]

What is a good value for the condenser?

I'm showing about 274 nF of capacitance.

I think that's about .274 Microfarads. My shop manual says .18 to .22 is in-spec. I don't know if .274 is better or worse than that....

 

[Jeffrey F.]

This saw is just filthy.... I got the phenolic disc and pump shaft out of the oil pump, I have PB blaster soaking it. I'm crossing my fingers that it works, especially if it has one of those tiny check balls like in a Mini Mac.
I will also need to clean up the bore for the disc and hopefully get it moving smoothly again.

Slow and steady on this rebuild....

View attachment 1212471View attachment 1212472

If you need any gaskets or diaphragms made let me know.

 

[MacAttack]

If you need any gaskets or diaphragms made let me know.

Thanks Jeff!

I'll let you know if I end up needing anything made. I think once I get a good spark the saw will run.