Mcculloch CP125 reborn

[rwoods]

Lee, when I was looking for a replacement kart flywheel I ran across a piece that stated the 125C had a 5 degree flywheel but I can't find it now (even if I did it doesn't mean it would be right). I thought it odd that the standard kart would have less advance than a saw but I did not pursue it further as I replaced the flywheel with the same as I removed. I think you are right as the part number of: a 101B 5 degree is 68280, 101B standard is 68281 and the 125 and MC101D is 68282 (includes pawls); the MC101D lists the 5 degree 68280 as an accessory. Ron

 

[cpr]

No module Lee.

I looked at the 2 125 flywheels I have and the 2 101s. All are mounted, so I can't see the key (don't feel like popping them, it's friggin' cold in the shop). The 125C has a cast "2", the other 125 a cast "1A". One 101 has no marks, the other a stamped "5" on top of one of the spring bosses.

 

[Brian13]

Did you use NOS seals? Is it possible you have a bad seal and its leaking?

 

[leeha]

Did you use NOS seals? Is it possible you have a bad seal and its leaking?

Yep, NOS seals. But this saw runs so nice on the floor
that i hardly believe it is sucking air. It was at first but
i found the stuffer had a pin hole. Once i fixed that it
responds well to carb adjustments.



Lee

 

[Brian13]

Seems like if its running hot enough to get the muffler red hot, it might be leaking somewhere.

 

[Dennis Cahoon]

My guess with running hot and lack of power......the timings to far advanced.

 

[leeha]

My guess with running hot and lack of power......the timings to far advanced.

If the timing is to far advanced, How do you retard it.
I could close the point gap some. But this saw is set up
exactly like all my other 123cc Macs.
Points are set at .020 and running 100LL avgas.
Flywheel looked to be like any other i have seen.



Lee

 

[cpr]

Wouldn't the crank be relared to timing also since it has a cam for the points?

 

[leeha]

Wouldn't the crank be relared to timing also since it has a cam for the points?

If the cam on the crank were worn, That would
retard timing.




Lee

 

[Jacob J.]

Lee- how is the intake boot on this one? Is it sealing on the manifold tight?

I know you've probably made sure it's good but as you know sometimes the boot can leak just enough air to fool a person.
What I've done when I suspect a leaking intake boot is coat the inside of it with a thin layer of grease and see if the saw runs
good for a few minutes until the grease sloughs off. Those Mac boots can crack in places where it's extremely difficult to see.

 

[Dennis Cahoon]

I know when I bought my 101B it came with 2 flywheels. Not sure what degrees though.

 

[heimannm]

The one Charles describes above with the "5" stamped on it is the 5° flywheel for the kart engines, not sure about the others.

Mark

 

[leeha]

Lee- how is the intake boot on this one? Is it sealing on the manifold tight?

I know you've probably made sure it's good but as you know sometimes the boot can leak just enough air to fool a person.
What I've done when I suspect a leaking intake boot is coat the inside of it with a thin layer of grease and see if the saw runs
good for a few minutes until the grease sloughs off. Those Mac boots can crack in places where it's extremely difficult to see.

I have looked at the boot several times and it is in really nice shape.
Not cracked or hard. It's like new. It pops on the intake nice. I use
stp to lube it and it pops on no problem.
Once it's running it doesn't change.
I'm going to check out some flywheels later today and compair
with whats on the saw.



Lee

 

[NORMZILLA44]

I haven't messe'd with a point's saw in year's. Can you adjust the air gap on them? Like saw's toady. If so have you checke'd the air gap lee?

 

[watsonr]

I would think air gap would be able to change the timing slightly by closeness to the flywheel...but maybe only 1 degree or so.

I have an SP that acts the same way. 155lbs compression, starts easy, idles nice, 4 strokes and full adjustable with carb screws but just doesn't cut it like it should. I'm curious to see what you find Lee. Have you looked at the bar, is it the narrow tail that may need the spacers to keep it off the chain?

 

[leeha]

I haven't messe'd with a point's saw in year's. Can you adjust the air gap on them? Like saw's toady. If so have you checke'd the air gap lee?

All the gaps are correct. The air gap between coil and flywheel
won't change timing or to any degree. Point gap will. The wider
the point gap the more advance timing you get. These are set
to factory spec at .020

I would think air gap would be able to change the timing slightly by closeness to the flywheel...but maybe only 1 degree or so.

I have an SP that acts the same way. 155lbs compression, starts easy, idles nice, 4 strokes and full adjustable with carb screws but just doesn't cut it like it should. I'm curious to see what you find Lee. Have you looked at the bar, is it the narrow tail that may need the spacers to keep it off the chain?

Has the correct bar. No spacers needed. Chain rotates very smooth.
I will let you know what i find. Might be awhile.



Lee

 

[watsonr]

What about the clutch slipping? A small enough amount you really can't see..but feel like its not cutting up to par? Check the wear on the drum?

 

[leeha]

What about the clutch slipping? A small enough amount you really can't see..but feel like its not cutting up to par? Check the wear on the drum?

Clutch and drum are brand new. It's the motor that bogs
when you try to lean on it.

 

[RandyMac]

Drop the point gap to maybe 18 and try that. Did you try the timing light trick? I know where an article on that is.

 

[watsonr]

Lee,
I looked at my CP flywheel, the only mark I see is the arrow pointing to the edge which would mark the break in the points for timing. I looked at the SP's I have and they have either a 1A or a 2 marked on them and all of them are single keyed....if that helps any.