McCulloch Mini and Small CC Chainsaw's

[heimannm]

Hey Joey, I don't mind working on the Mini Mac saws and have rebuilt several for guys that like them. I will use these for parts, or may put one or two together with needed parts and see if I can sell them locally.

Blisters - the 10-10S is a 57 cc version and are pretty nice saws. Check for spark, the 10-10S has a electronic ignition and if there is no spark you will have to find a new coil.

If there is spark and good compression, see if you can get it for $100 or less. You will probably need to install a carburetor kit which will cost $15 to $25 depending on where you find it (should be a Walbro SDC carburetor). I have a few of that model and like using them but I like my PM55 even better. Same basic saw but with the short clutch cover, just seems to be more nimble.

Mark

 

[Blisters]

Hey Joey, I don't mind working on the Mini Mac saws and have rebuilt several for guys that like them. I will use these for parts, or may put one or two together with needed parts and see if I can sell them locally.

Blisters - the 10-10S is a 57 cc version and are pretty nice saws. Check for spark, the 10-10S has a electronic ignition and if there is no spark you will have to find a new coil.

If there is spark and good compression, see if you can get it for $100 or less. You will probably need to install a carburetor kit which will cost $15 to $25 depending on where you find it (should be a Walbro SDC carburetor). I have a few of that model and like using them but I like my PM55 even better. Same basic saw but with the short clutch cover, just seems to be more nimble.

Mark

I'm thinking of offering him 70 for it. And the 28 bar and chain. If I get it, it will be my first Mac! Thanks for the info Mark, that helps.

 

[heimannm]

Some projects coming up.



Mark

 

[rwoods]

Mark, I have two PM6As and a SP40 that I picked up several years ago when overwhelmed with nostalgia. Not feeling too nostalgia since, so I am not sure what to do with them. Never tried to start any of them. The SP 40 was said to be a runner with a fuel leak. Either model worth fixing to use when my 036 gets too heavy? My memories aren't reliable enough for me. It has been 45 years since I last ran a PM6A and almost 35 years since I ran a PM510. I remember both being hard starters (probably not tuned correctly) and the 510 being a screamer with a problematic junk plastic starter housing. Ron

 

[heimannm]

The longer I am in the collector scene the more I hear about tree service companies lamenting that the PM6 went away. One fellow I got a truckload of stuff from (tree service and McCulloch dealer) said the PM6 was the best bucket saw ever and he became a Stihl dealer after McCulloch went away. If I were to choose I would tackle one of the PM6 saws. The fuel filter/fuel line is like nothing you have ever seen before but the parts can be found if you need them. I find both of my runners to be pretty reliable starters, maybe 8-10 pulls if they have been sitting for a long time, 6 to 12 weeks is not uncommon in my case. I do carry the later model PM6 with a chain brake in my truck all the time "just in case"...

I don't like the soft feel of the anti-vibe in the SP40/PM510 models.

Mark

 

[Blisters]

Well I got the 10-10s running. Sounds like a screamer till u throw it in some wood then it bogs and acts like I'm killing it. Is it a dirty carb?

 

[heimannm]

Try adjusting the H jet open, start with 1/4 turn and work from there. If it is screaming out of the wood it is probably too lean; keep opening the H until it just starts to burble WOT out of the wood. It should clean up and run just right once you put it under load.

Mark

 

[Blisters]

Try adjusting the H jet open, start with 1/4 turn and work from there. If it is screaming out of the wood it is probably too lean; keep opening the H until it just starts to burble WOT out of the wood. It should clean up and run just right once you put it under load.

Mark

Thanks Mark.

 

[heimannm]

Let us know if that does it for you. The 57 cc models are generally pretty nice little saws.

Mark

 

[rwoods]

Thanks, Mark. I have a couple NOS fuel lines for the PM6.

The seller of the Sp40 said it started leaking after he replaced the lines and he wasn't up to tearing into it again. Not sure how they are configured so I don't know if it is an easy fix or a pain.

Ron

 

[heimannm]

The SP40 does not require complete disassembly to service the carburetor, I don't remember how the fuel lines are routed.

Mark

 

[Car-guy2]

Before you put the automatic oil pump together, make sure it is correctly assembled and that it is working. There is one check valve in the top of the pump housing that is not accessible or serviceable so making sure not will avoid having to pull the front off the housing and removing the fuel/oil tank to change it later. The empty hole is the inlet, the one with the tube sticking out of it is the outlet to the bar. Put a drop or two of oil in the inlet hole and work the piston manually a few times, you should see the oil oozing out the discharge tube. The o-ring seal at the base of the automatic oil pump is a standard 020 o-ring, 1" O.D. and 7/8" I.D. They will cost $5.00 to $10.00 each if you buy them by the McCulloch part number 110653 off e-bay, or $0.50 to $1.00 or so each if you buy them from a bearing/hose shop, or $4.50 for 100 pieces from McMaster Carr + $6.00 for shipping.

View attachment 506360

The pump parts in order: pump body, adjuster sleeve, spring, piston assembly, and the o-ring seal.

View attachment 506370

The sleeve will only fit one way into the pump body and allow you to actually adjust the flow.

View attachment 506371

At this point I stopped taking photos, but reassembly is pretty straight forward. The biggest problem I have every time is getting the throttle rod reconnected. I find it is easier for me to remove the spring and take the throttle trigger and arm off the saw and get it connected, then reassemble the trigger to the housing and reconnect the spring. Your experiences may be different.

The little saw started right up and with a bit of adjustment would idle, rev, and oil as it should. I handed the saw back to the owner, we'll see if he can eventually come up with the $110 I had in parts.

Mark

Great info Mark. I just acquired my first mini Mac, an eager beaver 2.0. Picked it up at a yard sale for $10.

Besides the usual fuel line and carb. issues, it had a lot of bar oil in the crankcase. I've ordered a nos oil pump assembly, but was wondering if there should be any kind of check valve in the pulse port of the crankcase. I'd rather not have to tear this thing down more than once. Thanks again for the great info

 

[heimannm]

Actually you can just pull the front cover off and work on the oiler without having to take it completely apart again, but to your real question no, there is no valve; the automatic oil pump works on the crankcase impulse which means you need both positive and negative pressure to work the large piston (the phenolic disc on the oil pump, item 6 below) back and forth. the small end (the thin rod, item 7 below)) is the actual piston that is pumping the oil and the o-ring (item 5 below) holds it all together.

In addition to having the pump in good condition so oil can't leak past the small piston (the thin rod) there is an o-ring that seals the pump body to the crankcase bottom. I now know that the o-ring is a standard size -020 with a 1" O.D. and 7/8" I.D. (item 12 below).

It seems that the automatic oil pump body on those were subject to wearing and that allows oil to leak past into the pump body, from there it will drain back through the pump into the crankcase. It will all make sense when you have it apart and look at it.

All of the direct drive McCulloch saws that have an automatic oiler have used the same type of impulse operated oil pump from the time of the 640, 700 Series (740, 790, 795), all of the 10 Series, even the CP125 and later SP105 and SP125. the only ones that I have encountered with oil leaking past the piston have been the Mini Macs. I don't have any experience with the 300 Series saws but they have a very similar pump to the Mini Mac saws.

The 600 Series saws (610, 605, 650, Timber Bear 3.4, etc.) have a similar pump as well, but use a couple of diaphragms in addition to the pump body. Sadly, they are just as prone to leak oil into the crankcase and require the diaphragms to be replaced when they do start leaking.

Mark

 

[Car-guy2]

I do have it apart now and with your explanation it does make sense. So the cause of oil leaking into crankcase is wear on the thin pump rod and the pump body that it travels in. I'm glad I was able to find a complete assembly new and didn't take a chance on a used one. Now I just have to wait for it to get here. Thanks for your help Mark

 

[heimannm]

I believe that is correct, there is no other path for the oil to get from the pump to the crankcase except back through that small channel in the oil pump itself.

It is worth noting that the MM is the only saw with the oil tank above the automatic pump and the impulse port at the bottom of the crankcase. Seems like that might have been a bad decision.

Mark

 

[Car-guy2]

Do you know the metering lever setting for the zama carb. on this EB 2.0? It was well below the gasket surface, so I raised it up even with it. Now I'm wondering how it got that low if it's supposed to be flush with the gasket surface.
Also not sure of the carb model number. It has "M7" and "26Q" and "12” stamped in the pump cover.

 

[Blisters]

Do you know the metering lever setting for the zama carb. on this EB 2.0? It was well below the gasket surface, so I raised it up even with it. Now I'm wondering how it got that low if it's supposed to be flush with the gasket surface.
Also not sure of the carb model number. It has "M7" and "26Q" and "12” stamped in the pump cover.

I have a 10-10s with the large clutch cover. The recoil on it sticks when u pull it. Some screws have been lost and were replaced with what looks like electrical screws. Came.to me this way. U can loosen screws and it will then recoil the starter rope. What is the problem here? Is there an easy fix? Does anyone have a new one or a good used one?

 

[Car-guy2]

I got my eager beaver 2.0 back together with the new oil pump and a new o-ring to seal the pump to the crankcase. It fired after a dozen or more pulls with the choke on then idled and revved decent, but is smoking like a freight train. After a minute or two it died. I think it's still pulling bar oil into the crankcase. I don't know what else to do to it. Anybody have any ideas how to stop the oil from getting sucked into the engine? Thanks in advance.

 

[heimannm]

Most likely the crankcase was already filled with oil. It may take a minute or two before it all burn off.

Check your spark plug, there may have been enough oil in the crankcase to foul the plug. On a few saws that have been sitting with the oil tank full a significant amount of oil has leaked into the crankcase, so much so that I had to pull the plug and crank them over several times to clear them out. This can happen with bigger saws as well (550, 795) that are virtually hydrolocked when you first pull them over.

Mark

 

[Car-guy2]

You might be right. I cleaned the plug and ran it some more. Seems to be clearing up. Still smoking, but not as bad. The oiler is working cause I've got oil coming out under the clutch cover when I run it (no bar and chain on it yet). I'll run it some more and see if it clears up. Thanks for the help Mark.