The unofficial Mac 10-10 thread

[fossil]

Hi folks, My parts lists aren't helping me today... Could one of you kind folk provide me with the part numbers for the short, chain brake/clutch covers used on the 7-10 and Pro 10-10 Automatics? I have come across someone who cleared out an old dealership and amongst other NOS stock, there are Mac parts . Are there any "unicorns" or "hens' teeth" that I should be asking about for amongst this stuff?
On another track, have any of you had success in welding these clutch/chain brake covers? I have a couple that have cracks at or near the chain tensioner...

The 10-10A brake is the same PN

 

[Teemore]

View attachment 786352

The 10-10A brake is the same PN

Much appreciated that helps me out! - my original Pro 10-10A and SP 55 part lists are dated 1975 and 1973 and lack reference to the chainbrake...

 

[fossil]

Here's a late 7-10 IPL with the brake. No PN in the first section, scroll to the brake explosion figure 3

Rare stuff on the 10 series are the domed AF covers. Conversion kits from bullfrog carbs to SDC's as well.
Some auto oiler ring- pistons (round disc)

Any ten series muffler covers which are getting scarce as well.

 

[mogulmasher]

Ya I bought some of that Amazon fuel line for my very first Mac 10-10. Stuff hardened and became unusable first time fuel hit it. Absolute junk.

The hardened fuel line on this 2-10 is the original line it looks like. I'm gonna buy one of the glue in tank grommets from eBay and run regular tygon with it.

So I tried running the 2-10. It started no problem, but then runs wide open! Throttle input had no effect on rpms at all. Never been inside the flat Mac carb, anything in there cause this kind of a problem? It's running fast enough that I think it's something more than an air leak somewhere.

 

[Jethro 2t sniffer]

So I tried running the 2-10. It started no problem, but then runs wide open! Throttle input had no effect on rpms at all. Never been inside the flat Mac carb, anything in there cause this kind of a problem? It's running fast enough that I think it's something more than an air leak somewhere.

Hahaha good luck man Mark may be of help I think everyone else has gave up

 

[fossil]

One thing you might check is to look at the throttle plate. If it's in backwards they will appear to run full throttle. I know that from experience. I fired up a 77cc XL-902 AM with the plate in backwards for a test cut . I forgot to hook up the kill switch wire and the choke rod.

I couldn't stall in wood no matter how hard I pushed. Not feeling like getting a shock I pulled off the AF cover and filter and choked it with my thumb.

It was a moment of panic. I figured there would be Homelite parts scattered all over the place.
No laughing please.

 

[vizette]

91249 - the "housing assembly"? Which is the cover, but the description is somewhat misleading in my opinion, as it's not the whole functional chain brake, that part number is literally just the bare cover. Same p/n in both the 7-10a and 10-10 IPLs I spot checked.

Welding - I've seen it discussed but have no experience with. You'd need someone with TIG skill. I'm actually curious if anyone has tried patching cracks with the aluminum "welding" rods that you can use with a propane/mapp torch.

 

[mogulmasher]

One thing you might check is to look at the throttle plate. If it's in backwards they will appear to run full throttle. I know that from experience. I fired up a 77cc XL-902 AM with the plate in backwards for a test cut . I forgot to hook up the kill switch wire and the choke rod.

I couldn't stall in wood no matter how hard I pushed. Not feeling like getting a shock I pulled off the AF cover and filter and choked it with my thumb.

It was a moment of panic. I figured there would be Homelite parts scattered all over the place.
No laughing please.

Ok will do.

 

[mogulmasher]

Hahaha good luck man Mark may be of help I think everyone else has gave up

Guess I'm a glutton for punishment, cause I picked up another flat back carbed Mac yesterday. Lol

 

[fossil]

91249 - the "housing assembly"? Which is the cover, but the description is somewhat misleading in my opinion, as it's not the whole functional chain brake, that part number is literally just the bare cover. Same p/n in both the 7-10a and 10-10 IPLs I spot checked.

Welding - I've seen it discussed but have no experience with. You'd need someone with TIG skill. I'm actually curious if anyone has tried patching cracks with the aluminum "welding" rods that you can use with a propane/mapp torch.

No That's not it. Look at the first line in the parts chart from the IPL and you will see PN 91278 "CHAIN BRAKE Assembly"

I would be wary and make sure if you are buying one that they aren't using 91278 for the bare housing.


The aluminum rod from Hobart that claims it's for mag too didn't work worth a darn.

 

[Goinwheelin]

Got the pro 10-10A back together last night. What started as very clean saw with a no spark issue, evolved into a complete tear down/refurbish only to find out later it was just a bad plug wire I have this “while I’m in there” philosophy when it comes to replacing parts and it just snowballed from there. Next thing I knew the dremel was out, and I’m opening up the exhaust ports and port matching the muffler lol. Oh well it’s all in good fun and if I’m going to practice something like that a 10-10 is a good start.

 

[heimannm]

mogul - take a look at the throttle movement to see how far it is actually moving. There were at least 5 variations of the "bullfrog" style carburetors and each were different with variations in the throttle linkages, etc. The "H" adjust is actually controlling how far the throttle butterfly is opening while at the same time controlling how far the needle is being withdrawn from the carburetor. As Fossil has noted, the throttle butterfly is not centered on at least some of the models and installing it backwards would result in much less variation in the air flow.

Mark

 

[mogulmasher]

I'll check that out tonight. Thanks Mark!

 

[2broke2ride]

I'll check that out tonight. Thanks Mark!

Guess I'm a glutton for punishment, cause I picked up another flat back carbed Mac yesterday. LolView attachment 786414

I would love to know how you come up with all of these lol. I never catch Macs for sale around here. I know you do most of your trading on craigslist, are you using a mobil app or PC? I'm starting to think my craigslist mobil app sucks.

 

[mogulmasher]

I would love to know how you come up with all of these lol. I never catch Macs for sale around here. I know you do most of your trading on craigslist, are you using a mobil app or PC? I'm starting to think my craigslist mobil app sucks.

I don't do anything fancy Kevin. I do search cl for the most part but do have eyes on fb marketplace too....it's just the good deals disappear fast on there. I do get automatic email alerts when Macs pop up, but those are rarely good deals.

My best scores are usually searching simply for "chainsaws" for sale or "vintage chainsaws". Those are the people selling lots of saws or maybe a saw that they don't know what it is.

 

[Maintenance supervisor]

91249 - the "housing assembly"? Which is the cover, but the description is somewhat misleading in my opinion, as it's not the whole functional chain brake, that part number is literally just the bare cover. Same p/n in both the 7-10a and 10-10 IPLs I spot checked.

Welding - I've seen it discussed but have no experience with. You'd need someone with TIG skill. I'm actually curious if anyone has tried patching cracks with the aluminum "welding" rods that you can use with a propane/mapp torch.

I've had very good results with slow cure JB weld.

 

[Maintenance supervisor]

Hi folks, My parts lists aren't helping me today... Could one of you kind folk provide me with the part numbers for the short, chain brake/clutch covers used on the 7-10 and Pro 10-10 Automatics? I have come across someone who cleared out an old dealership and amongst other NOS stock, there are Mac parts . Are there any "unicorns" or "hens' teeth" that I should be asking about for amongst this stuff?
On another track, have any of you had success in welding these clutch/chain brake covers? I have a couple that have cracks at or near the chain tensioner...

I need a big 10-10 A airfilter if you find one.

 

[vizette]

I've had very good results with slow cure JB weld.

If duct tape and zip ties won't fix it, JB Weld it!

I know people scoff at it a lot, but it really is amazing stuff when applied/used properly.

 

[Teemore]

I need a big 10-10 A airfilter if you find one.

Let me know the part number and I'll make enquiries.
I have already passed on a "few" part numbers for them to look for but I'm not holding out a lot of hope as they commented about having cherry picked larger NOS parts and that makes me think that they overlooked a lot of the "smalls".

 

[Maintenance supervisor]

If duct tape and zip ties won't fix it, JB Weld it!

I know people scoff at it a lot, but it really is amazing stuff when applied/used properly.

It is but it has its limits, sealing gas tanks and fixing the fracture in the clutch cover is perfect.
I've also built almost 1/2 a starter cover bottom with it.