McCulloch Chain Saws

[joeymt33]

There is a sealant used when installing those bushings. You may have to punch it out and reseal it with some fuel tank sealer.

 

[ethar]

Joey like the half kart half chainsaw models of the 60's and 70's or the partner/mcculloch monster. I don't know who was the lead design over the years but whoever it was made some definite frankensaws. But you gotta consider Mac was at the top of the industry for years so it worked for them. I'm not 100% but Mac did partner with quite a few other manufacturers to come out with some hybrids.

 

[machinisttx]

And once again, as with all things McCulloch, there are no absolutes. The 650 that I picked up has the compression release port (now plugged), and was fit with a 48" bar before I got it.

Mark

48" on a 60cc saw? Did it at least have full skip on it?

 

[OldDeadWood]

But, you're right. There were no absolutes. McCulloch made their own frankensaws.

Joey

Would that be a FrankenMac&cheese?

ODW

 

[joeymt33]

And a side of mini Mac bites.

 

[AKDoug]

Got my SP125 running today. Still runs pretty fat on the top end. I'm going to get a carb rebuild kit. It has a Tillotson HS124A in it and I'm not sure how to adjust it.

Tried multiple times to post video to no avail.

 

[joeymt33]

Got my SP125 running today. Still runs pretty fat on the top end. I'm going to get a carb rebuild kit. It has a Tillotson HS124A in it and I'm not sure how to adjust it.

Tried multiple times to post video to no avail.

I think those carbs have a fixed high jet. The one and only adjustment screw is the low adjustment. You could get a walbro SDC-20 which would be a direct swap and have an adjustable high side.

 

[AKDoug]

Thanks for the infor leeha had the same thing to say.

 

[joeymt33]

You're welcome, great saw you got there.

 

[AKDoug]

Now I just have to find a carb for it. Can you replace the high jet internally on those Tillotson carbs?

 

[joeymt33]

I'm not sure about replacing just the jet. I would think you could.

I would just get the SDC 20 and make it tuneable. <---is that a real word? Or just an Alabama word? Anyway, tune that a little rich and put a long bar on it so you can make it work.

 

[Eccentric]

Now I just have to find a carb for it. Can you replace the high jet internally on those Tillotson carbs?

You can indeed change the high speed jets on the HS. Here's the jet list from the SP125C IPL. Not sure how easy those jets are to find. You can also affect the high speed operation with the L speed needle setting. It only does so much however.

Getting an SDC20 would be simpler from a tuning perspective. Guys aren't in a hurry to get rid of those however. May take a while to land one....

88771 1 Jet - High speed fuel (029 std.)
88772 Jet - High speed (028) Alt.
88781 Jet - High speed (027) Alt.
88780 Jet - High speed (026) Alt.
88769 Jet - High speed (030) Alt.
88770 Jet - High speed (031) Alt.

 

[AKDoug]

I'm never going to find anything over 24".. I have a 20" log in my pile, but at -16F, my excavator didn't want to play.

 

[joeymt33]

Well then at least get a .404 8 tooth sprocket and and bury it. It's just begging to be worked.

 

[AKDoug]

You can indeed change the high speed jets on the HS. Here's the jet list from the SP125C IPL. Not sure how easy those jets are to find. You can also affect the high speed operation with the L speed needle setting. It only does so much however.

Getting an SDC20 would be simpler from a tuning perspective. Guys aren't in a hurry to get rid of those however. May take a while to land one....

Thanks for the info. I spend 20 years tuning 2 stroke dirt bikes and snowmobiles that required changing jets. The low speed jet did lean things out and sped the saw up, but that just resulted in lower performance when it was loaded a little bit. I'll keep my eye out for that carb. There's no real hurry to get this saw running. I have another project starting next week.

 

[AKDoug]

Just out of curiosity, what kind of RPM are you guys finding when it's properly four stroking and cleaning up in wood?

 

[Eccentric]

I've never tach'd them. Just tuned them by ear in the wood. They need fuel to make power and stay alive.

 

[joeymt33]

If I had to guess, 7500 to 8500. But like Aaron said, I've never tached one and i actually own a $100 non contact tach and I've had a sp125. Don't go off what I said, it could be out if that range. That's just a guess from running them.

 

[joeymt33]

Maybe Lee will enlighten us soon. He has forgotten more than i know about the Big Macs.

 

[ethar]

I've got an old Mac 380 and when it is running at all I know it's gotta be hitting atleast what your guessing there Joey. Only thing I can't understand I've cut with a few 250's and some bigger saws they feel like the cut slower than my 10-10 or 610.