McCulloch Chain Saws

[AKDoug]

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.

While mine was running the way it was in the video, it was hitting 8200 unloaded.

 

[joeymt33]

That's not surprising, properly tuned it should be a lot more than that unloaded. I would think 8200 rpm would be close to engine speed while cutting

 

[RedFir Down]

Hello guys! I have a 3-25 on the bench right now that Im trying to get running for a friend of mine.
The saw appears to have good compression, It has good spark so now im moving onto the fuel side of things. I pulled the carb yesterday and the diaphragm is shot.
Is that diaphragm "molded" into the carb or is it just stuck in place?
Im sure it would be a miracle to find a new diaphragm someplace, so is there a way to make one?

If you guys want a picture (just for the heck of it) of the saw let he know I can put one up later today.

Thank you!!

 

[ethar]

Theres only one person on here I would know would have parts for that. Look up heimannm.

 

[Mac 6-10]

My CP-70 arrived today. Looks like I did well for 20 bucks. All the mounts are perfect. The intake boot looks great. The cylinder and piston look great as well. I just need to split the case and get all the dirt and rust out of the cylinder from the junk muffler. I got a parts 10-10 from struggle to complete this saw. I still need an air filter cover if any one has one.

 

[heimannm]

Joey - The BP399T is just fine. There were a few different opinions on the sudden stoppage at the GTG, pistons warming up too fast was a popular choice. I think there is a chance that in the excitement, the fuel line got pulled out of the tank... It restarted right away and ran as well as ever and when I got home I pulled the exhaust to have a look and it appeared to me just like the day it arrived. There are a few scratches but those came when it was test run at the factory. I am still looking for a lightweight chassis like a heavy duty kart or mini dune buggy to put this one to use.

AKDoug - I have the fixed jet carburetor in the SP125 I take to the woods, it is pig rich out of the cut but you can lean on the saw and it clears up in the wood. If you plan to keep that saw for the long term you might want to consider keeping the fixed jet carburetor to avoid any potential for running it too lean.

Nick - Joey is spot on, there was a small tube of sealant in the kits to seal the passage of the fuel line. You might try sealing it in place, but it may well be necessary to take it apart and start over. If I recall correctly, the aluminum bushing has a step, may even be tapered, you might get lucky by just pressing it firmly in place.

6-10 - I can probably find an AF cover if no one else comes up with one. Do you have a good RH starter to put on that CP70? What about the sawdust screen for the flywheel cover? I should have some good used bits in the attic if it comes to that. I have CP55 that I like to use from time to time, nice little saw that is more productive than my Jonsered 2050 even though the J'red is about 30 years newer. I have one CP70 that runs but is pretty worn out so I don't use it for cutting wood. I have another CP70 in better condition that I put together this year but haven't done anything more that a little pine cutting with that one.

I will be home for a couple of days so I am finally getting to the Mini Mac my son dropped off a few months back. Right now I have it completely disassembled and will need to check in the attic tomorrow to see if I have some new rings, I already found the crankshaft seals, after that it should go back together and I can move on to something slightly more rewarding.

Mark

 

[joeymt33]

Mark, I could put that bp399 to use. I can come pick it up on my next visit. You good with that?

 

[MS460WOODCHUCK]

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.

That's because they are cutting WAY slower...

 

[Mac 6-10]

Pulled the engine apart this morning to find the piston and cylinder in great shape. Just needs a real good soak in the parts washer. I found a set of new rings I'm going to install while its apart.

 

[tricky50]

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

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

Mark,
I just picked up a McCulloch 605 and don't have a manual with it. Do this saws hav a compression release switch
some where?

Thanks
Tricky

 

[joeymt33]

The 605 should not have a decomp.

 

[joeymt33]

See the red button? That's the decomp location on the 600 series.

 

[tricky50]

The 605 should not have a decomp.

joeymt33,
Thank you for the decomp info.

tricky

 

[fossil]

SP80 carb to cylinder intake sealing.

I will be putting my SP80 back together a soon as the clear coat cures and was wondering if I should be putting any sealer on The rubber boot between the carb box and the cylinder insulator. It looks and feels to be in good condition.

Thanks

 

[joeymt33]

I don't. I just use an original mcculloch gasket in good shape.

 

[joeymt33]

There's not a gasket as you know on the
Boot. I usually don't put any sealer on the ends of the boot unless the metal or rubber is pitted.

I first read your post and thought you were asking about the carb gasket only. I thought I'd clarify.

 

[fossil]

Thanks. I have a new carb gasket and made another for the insulator to cylinder.
I was just wondering if the boot was a chronic leaker or was usually OK. It's not hardened up.
Am I right in assuming the large wire spring is a ground connection to keep the old guy's hair from standing on end?

 

[joeymt33]

He spring keeps the ground connected so the kill switch works. The later models had a cable attached to the front AV

 

[heimannm]

John - If you saw a good 250 you might change your mind. At Baraboo each August Scott (McC) normally takes the 5 In³ and under class with a 250, my SP81 was lagging way behind. I will blame it partially on the poor bar and chain, but that 250 will flat out run, his son Pete has a 1-51 that is just barely behind it.

I think the reason we all expect the large frame front tanks saws to be slow is we only encounter worn out saws, in good shape they have some real capabilities.

Joey - please stop by when you are in the area and I will listen to your story, if it's good enough I may just send one home with you.

And for those of you that were waiting on the edge of your seat, the Mini Mac is done...

11:00 this morning


3:00 this after noon, I spent about an hour and a half on the carburetor to insure it was alright before I put it together.








New rings, replace the crank shaft seals, carburetor rebuild, replace the rope, new AF & choke knob plus the top handle and clutch off a parts saw. Now that this one is done I can move on to something more interesting so stay tuned.

Mark

 

[joeymt33]

Mark, I now need a good reason to justify that BP snowmobile engine.

Also, thanks for reporting back about the mini Mac. I was on the edge of my seat. I had the whole fam waiting around the computer waiting for your report back. You could not build another saw now, I'm fulfilled.