McCulloch Chain Saws

[ThistleIA]

How hot does your starter cover get running it for an hour or so?
Even with header wrap on my muffler that thing still seems to generate quite abit of heat.

I haven't really noticed,just had it 2 yrs next month,havent used it more than 30 min at a time since getting it.It sat for several months between uses.Since I retired there's more free time now (HA!) so I'll keep watch on anything unusual.

 

[rwoods]

Ran the PM800 today, cut up 5/6 dead pines and a couple cookies off a pecan.
Its incredibly difficult for me to hear the tune of this McCulloch with that funky muffler. I switched the chain from a .404 chipper to. 404 square chisel 24" bar and it pulls like a train but doesn't seem to wind out like the 700 and I don't want to grenade it lean after putting it together.
The old McCulloch dealer said it probably justs needs some run time after the the scotch bright pad treatment and ring swap which might be true.
I'm just used to the loud BRAP! Of the other Macs for tuning purposes.
Anyone else notice a "break in" after honing the cylinder with scotch bright pads?

Check the rpm with a tach. It is my understanding that the 800 should be higher than a 700. Also in the cut the 800 would likely be close to 10k with the 700 around 9k. I have never measured my 700 but it has never seemed to rev like the 800.

Ron

 

[rwoods]

Am very tempted to put a stock 850 muffler on my otherwise strong running 800.Used the 850 on Tuesday & even though in the past I didn't think there wasn't much difference,the 850 has just a wee bit more snap.Everything is otherwise equal,same carb/tune,same chain etc.The 850 will snap my wrist if I forget to use the decomp button (and hold it in) where as the 800 with the Q port/no decomp is slightly easier starting with less compression.

FEIW the felt compression with the q port is deceiving. My 700 is 40 psi lower than my 800 and it is far more difficult to pull over. IME actual compression measured with hand pulls is about 5 psi higher in the the pre q port 82cc models over the q port 82cc models.

Ron

 

[Maintenance supervisor]

FEIW the felt compression with the q port is deceiving. My 700 is 40 psi lower than my 800 and it is far more difficult to pull over. IME actual compression measured with hand pulls is about 5 psi higher in the the pre q port 82cc models over the q port 82cc models.

Ron

I have a compression tester but no tachometer? What kind do you have Ron?

 

[Maintenance supervisor]

Check the rpm with a tach. It is my understanding that the 800 should be higher than a 700. Also in the cut the 800 would likely be close to 10k with the 700 around 9k. I have never measured my 700 but it has never seemed to rev like the 800.

Ron

"In the cut "it would be difficult for me to evaluate the variables. They both have 24" bar and full comp chain currently but with both bars fully buried the 800 feels like it wants more! Bar. I can really lean on it but it was about 90°F today so I got hot and so did the saw after about an hour.

 

[heimannm]

I have an SP 70 that I rebuilt with a new piston and cylinder and used an NOS reed muffler. Starts and runs very well, but doesn't sound like a hot rod Mac should. I thought it seemed slow until I ran it against a couple of other 70 cc McCulloch saws and it was flat out much stronger. I will admit that tuning is a little more challenging without the Mac Cackle.



I think that particular saw is residing in the museum now but I may be mistaken.

Mark

 

[banshee1]

Long story short, a good friend left his girlfriend 3 months ago with a lot of bills overdue so I agreed to help her sell all but a couple of his chainsaws that she can use on the farm.
One of the last saws I need to deal with is a right hand McCulloch Mac 10-10.

I decided to tackle the carb 1st. Pulled it off without much problem but, did ruin the gasket so I'll have to make one. Pulled the diaphragms off without any hassle, so then I went to remove the mixture screws and the low side came out easy. The idle (or at least I think is the idle) came out a little harder. Then I go to remove the high screw and broke the damn thing off flush to the body. So now if I do get it running I have no way to adjust the high side. Put it in a tank of Seafoam to soak over the night to clean it (actually looks pretty clean but soaking it anyways). Hoping it will loosen up over the night so I can get it removed or at least adjust it. If I can get it out and it runs good I may look for a screw and cover the cost myself as she doesnt have money to put into these saws and not sell them right off. Anybody know where I might be able to find the high mixture screw?

While carb is soaking I pulled the flywheel off, checked the points and condenser and they look good and the condenser checks ok with my multimeter. So I reset the gap on the points and the coil and still dont have fire. No matter the position of the kill switch the lead is always grounded to the frame. So how in the h*ll do I get that damn switch apart?

Any help is appreciated as I've never worked on a McCulloch saw.
Thanks.

 

[rwoods]

I have a compression tester but no tachometer? What kind do you have Ron?

"In the cut "it would be difficult for me to evaluate the variables. They both have 24" bar and full comp chain currently but with both bars fully buried the 800 feels like it wants more! Bar. I can really lean on it but it was about 90°F today so I got hot and so did the saw after about an hour.

I don’t have a tach. Brian used some sort of tach that read off a reflective stripe when we did our little 82cc shootout several years back.

When I say in the cut, I actually mean when the saw is loaded in its sweet spot. How big a load of course varies with the saw.

The DE80 is governed at 10,000 and doesn’t seem to vary under a load. However, I am only going by ear.

IIRC I have read in some publication that the 700 under load is a 9000 rpm saw.

The above is consistent with what I was told in 1982 by a MAC distributor when I was choosing between a 700 and an 800. And in my experience my 700 is much slower than my 800 - what they are actually turning in the cut I don’t know. Brian has been meaning to check the 800’s rpm in the cut as he now has one of those little tachs but we either forget or just have too much work to take the time. With this discussion, when we do we will check a 1010 or two and the 700.

I may be all wet but I don’t think I am.

Ron

 

[vizette]

Then I go to remove the high screw and broke the damn thing off flush to the body. So now if I do get it running I have no way to adjust the high side. Put it in a tank of Seafoam to soak over the night to clean it (actually looks pretty clean but soaking it anyways). Hoping it will loosen up over the night so I can get it removed or at least adjust it. If I can get it out and it runs good I may look for a screw and cover the cost myself as she doesnt have money to put into these saws and not sell them right off. Anybody know where I might be able to find the high mixture screw?

I believe the needles are steel and the carb body aluminum, so if you want to get crazy, COMPLETELY disassemble the carb, and soak it in hot water that's saturated with Alum (the spice). It'll eat ferrous metal, but not non-ferrous. Google it for more details. I had a bolt that I was extracting bust off down inside the hole (saw tank), the alum ate it up with no affect on the tank. You'd have to get everything out of the carb though before soaking, choke plate, throttle plate, etc.

You said it busted flush, so theoretically you could use a dremel with a cutoff wheel to cut a slot in it. You'd cut into the carb body too, but getting into the body a little won't hurt anything. If the busted needle loosens up after a bit soaking, you could then use a screwdriver to back the needle out the rest of the way.

I have an extra set of long needles sitting around if that works. I don't think I have any short, but I can look. There's always feebay:

https://www.ebay.com/itm/NEW-MCCULLOCH-7-10A-HI-SPEED-NEEDLE-PN-67506/191412563952or m&d
https://www.m-and-d.com/MAC-M67506.html
(I just randomly chose a model for this part number, you should look up the correct one)

 

[Maintenance supervisor]

I don’t have a tach. Brian used some sort of tach that read off a reflective stripe when we did our little 82cc shootout several years back.

When I say in the cut, I actually mean when the saw is loaded in its sweet spot. How big a load of course varies with the saw.

The DE80 is governed at 10,000 and doesn’t seem to vary under a load. However, I am only going by ear.

IIRC I have read in some publication that the 700 under load is a 9000 rpm saw.

The above is consistent with what I was told in 1982 by a MAC distributor when I was choosing between a 700 and an 800. And in my experience my 700 is much slower than my 800 - what they are actually turning in the cut I don’t know. Brian has been meaning to check the 800’s rpm in the cut as he now has one of those little tachs but we either forget or just have too much work to take the time. With this discussion, when we do we will check a 1010 or two and the 700.

I may be all wet but I don’t think I am.

Ron

I think you guys are right as far as "its the muffler " messing with my tuning method. Everyone else seems to be saying that they have similar experience. The saw pulls hard and the throttle response is spot on so keeping with that I'll just run it for awhile.
What did you guys discover with your 82cc shoot out?

 

[vinnywv]

Long story short, a good friend left his girlfriend 3 months ago with a lot of bills overdue so I agreed to help her sell all but a couple of his chainsaws that she can use on the farm.
One of the last saws I need to deal with is a right hand McCulloch Mac 10-10.

I decided to tackle the carb 1st. Pulled it off without much problem but, did ruin the gasket so I'll have to make one. Pulled the diaphragms off without any hassle, so then I went to remove the mixture screws and the low side came out easy. The idle (or at least I think is the idle) came out a little harder. Then I go to remove the high screw and broke the damn thing off flush to the body. So now if I do get it running I have no way to adjust the high side. Put it in a tank of Seafoam to soak over the night to clean it (actually looks pretty clean but soaking it anyways). Hoping it will loosen up over the night so I can get it removed or at least adjust it. If I can get it out and it runs good I may look for a screw and cover the cost myself as she doesnt have money to put into these saws and not sell them right off. Anybody know where I might be able to find the high mixture screw?

While carb is soaking I pulled the flywheel off, checked the points and condenser and they look good and the condenser checks ok with my multimeter. So I reset the gap on the points and the coil and still dont have fire. No matter the position of the kill switch the lead is always grounded to the frame. So how in the h*ll do I get that damn switch apart?

Any help is appreciated as I've never worked on a McCulloch saw.
Thanks.

The switch has a screw holding it in place. It is located inside the handle above the trigger. Turn the saw upside down to see it. Likely will be hidden under sawdust and grime. Its a phillips i believe ,it goes into the plastic of the switch itself. Follow the wire to locate it. The wire is held in place by the screw. That plastic switch can be brittle so use caution. You may want to take the trigger clear out to see it better. A roll pin holds the spring and trigger in place.

 

[Max the Mac Man]

I don’t have a tach. Brian used some sort of tach that read off a reflective stripe when we did our little 82cc shootout several years back.

When I say in the cut, I actually mean when the saw is loaded in its sweet spot. How big a load of course varies with the saw.

The DE80 is governed at 10,000 and doesn’t seem to vary under a load. However, I am only going by ear.

IIRC I have read in some publication that the 700 under load is a 9000 rpm saw.

The above is consistent with what I was told in 1982 by a MAC distributor when I was choosing between a 700 and an 800. And in my experience my 700 is much slower than my 800 - what they are actually turning in the cut I don’t know. Brian has been meaning to check the 800’s rpm in the cut as he now has one of those little tachs but we either forget or just have too much work to take the time. With this discussion, when we do we will check a 1010 or two and the 700.

I may be all wet but I don’t think I am.

Ron

My problem is issues with the tachs themselves. I cant seem to find a good one. I have two $40-60 range tachs... neither read consistent or agree. My uncle has a third. Same thing they just are not consistent. Any recommendations tach wise? I usually just tune by ear and then check it with a tach as a curiosity. But would like to find one i trust.

 

[rwoods]

I think you guys are right as far as "its the muffler " messing with my tuning method. Everyone else seems to be saying that they have similar experience. The saw pulls hard and the throttle response is spot on so keeping with that I'll just run it for awhile.
What did you guys discover with your 82cc shoot out?

Pretty much that there isn't a nickel's worth of difference in the performance unless you lean one out and then shortly it will seize. Probably the fastest cutting saw I have ever run was my accidentally too lean 800 - it only lasted minutes. Brian's lasted longer, but none the less died. The 850 in our test was a fresh rebuild by Brian. The DE80 is a low hour saw - looks almost new. My 800 was rebuild by me and has several cutting seasons on it. It has the old style muffler and a coated piston.

Here are some old posts:

[/QUOTE]

Poge, I am listening too. I know that when too lean they will really scream and seem to be a lot more powerful. Below is from a test Brian did a year ago. RPM read off the clutch (no chain). Some weeks later Brian's saw seized. Not sure if he nailed down the cause or not. Also learned later that the DE80 has a "governor" in the carb. Ron

As promised in another thread, we check the rpm's of each saw. Brian's tach is a photo cell so we measured off the clutch drum. Results were a little surprising to me given my impressions which I will get to later. Brian's 800 - almost 12,900. 850 - right at 12,500. My 800 - around 11,700 then Brian discovered that the decomp was loose; tighten it up and it jumped to 12,300. DE 80 - consistently 9,900 to 10,000. Brian leaned it some and it hit 11,300 but we put it back to where it was originally tuned.

In the cut, Bryan's 800 felt the strongest. The other three were pretty much the same despite my 800 having an 8 tooth sprocket. Given my impressions, I was a little surprised by the max rpm difference of the DE 80.

The 850 had noticeably more vibration. Brian attributed that to the NOS stiff as a board AV mounts. I didn't seem to notice the screwed together AV mounts on my 800 as I had previously. I tweaked them a little when I had it apart the other day while working on the oiler. I am not sure whether or not Brian felt any vibration difference in the 800's.

During the rpm testing, my 800 hands down put out more oil so hopefully it is finally fixed.

Now let me work on that video.

Ron

My saw was lean when it let go. You can hear it in the videos. It was just a little too lean but would run like no tomorrow.

Brian

This to me is why the 800 muffler is bad. Its alot harder to hear that 4 stroking compaired to any saw ive owned or played with.. not many haha i only have 10 but yea maby ive got toast hearing already but i can never be happy with its tune allways second guessing and end up fattening it up again out of fear

Ron

 

[Maintenance supervisor]

Long story short, a good friend left his girlfriend 3 months ago with a lot of bills overdue so I agreed to help her sell all but a couple of his chainsaws that she can use on the farm.
One of the last saws I need to deal with is a right hand McCulloch Mac 10-10.

I decided to tackle the carb 1st. Pulled it off without much problem but, did ruin the gasket so I'll have to make one. Pulled the diaphragms off without any hassle, so then I went to remove the mixture screws and the low side came out easy. The idle (or at least I think is the idle) came out a little harder. Then I go to remove the high screw and broke the damn thing off flush to the body. So now if I do get it running I have no way to adjust the high side. Put it in a tank of Seafoam to soak over the night to clean it (actually looks pretty clean but soaking it anyways). Hoping it will loosen up over the night so I can get it removed or at least adjust it. If I can get it out and it runs good I may look for a screw and cover the cost myself as she doesnt have money to put into these saws and not sell them right off. Anybody know where I might be able to find the high mixture screw?

While carb is soaking I pulled the flywheel off, checked the points and condenser and they look good and the condenser checks ok with my multimeter. So I reset the gap on the points and the coil and still dont have fire. No matter the position of the kill switch the lead is always grounded to the frame. So how in the h*ll do I get that damn switch apart?

Any help is appreciated as I've never worked on a McCulloch saw.
Thanks.

Pictures would help incase it's a bullfrog carburetor

 

[PogoInTheWoods]

My problem is issues with the tachs themselves. I cant seem to find a good one. I have two $40-60 range tachs... neither read consistent or agree. My uncle has a third. Same thing they just are not consistent. Any recommendations tach wise? I usually just tune by ear and then check it with a tach as a curiosity. But would like to find one i trust.

Get one of these. Wireless. Very fast. Works great. Stores the highest reading. Rugged. Replaceable battery. Also works with 4-stroke engines. Can be left outside in the rain all night and still work after you drain the water out. I've had mine for years and would buy another one. Worth every penny. https://tinytach.com/handheld-tachometers

​

 

[PogoInTheWoods]

​

Here are some old posts:l.

I recall the discussion as I was also trying to get my 800 dialed in at the time. I did pretty well by ear, but was still a little lean as I recall. My ultimate method was repeatedly in and out of the wood until I could clearly hear the difference when it cleaned up in the cut. Put the tach on it out of the wood and ended up at 12,200 which is where I left it.There are no top end specs for the 82cc saws anywhere except what I discovered above for the 8200. Figured it had to be somewhere in the ballpark if they finally published something. Interesting that they show the 700 actually turning a higher RPM at maximum power.

BTW, 2nd column is max power RPM. 3rd is idle setting. 4th is clutch engagement. 5th is top no load RPM.

 

[banshee1]

I believe the needles are steel and the carb body aluminum, so if you want to get crazy, COMPLETELY disassemble the carb, and soak it in hot water that's saturated with Alum (the spice). It'll eat ferrous metal, but not non-ferrous. Google it for more details. I had a bolt that I was extracting bust off down inside the hole (saw tank), the alum ate it up with no affect on the tank. You'd have to get everything out of the carb though before soaking, choke plate, throttle plate, etc.

You said it busted flush, so theoretically you could use a dremel with a cutoff wheel to cut a slot in it. You'd cut into the carb body too, but getting into the body a little won't hurt anything. If the busted needle loosens up after a bit soaking, you could then use a screwdriver to back the needle out the rest of the way.

I have an extra set of long needles sitting around if that works. I don't think I have any short, but I can look. There's always feebay:

https://www.ebay.com/itm/NEW-MCCULLOCH-7-10A-HI-SPEED-NEEDLE-PN-67506/191412563952or m&d
https://www.m-and-d.com/MAC-M67506.html
(I just randomly chose a model for this part number, you should look up the correct one)

I'm hoping the Seafoam may loosen it up. Being a machinist I remember using something similar a long time ago to remove a broken tap in an aluminum part. It was nasty stuff.
Thanks for the info Vizette.

 

[banshee1]

Pictures would help incase it's a bullfrog carburetor

Bullfrog carb? That's a new one.

 

[banshee1]

The switch has a screw holding it in place. It is located inside the handle above the trigger. Turn the saw upside down to see it. Likely will be hidden under sawdust and grime. Its a phillips i believe ,it goes into the plastic of the switch itself. Follow the wire to locate it. The wire is held in place by the screw. That plastic switch can be brittle so use caution. You may want to take the trigger clear out to see it better. A roll pin holds the spring and trigger in place.

I looked last night, but it was getting dark and couldn't see anything. I'm headed back shortly so I'll look a little harder this time.
Thanks for the info Vinny.

 

[PogoInTheWoods]

Just pull the kill wire off the coil to check for spark. And just a thought..., if that needle was so 'stuck' it actually broke when trying to remove it, there's a pretty good chance the seat is so deformed the carb body may be junk and need replaced anyway. Shouldn't be hard to find.

And a bullfrog carb was used on very early 10 series saws. Not likely to be one on your 10-10, but rather a fairly common Walbro SDC variant.