McCulloch Mini and Small CC Chainsaw's

[MacAttack]

Sounds like the timing is seriously delayed. I'd start looking at the ignition.

I think you're correct, the more I think about it, I feel like I have a spark / timing issue going on. I never did check the points on this saw because it looked like a blazing hot spark when I tested it on the bench. I'm willing to bet the points are grossly out of adjustment... thanks for your input!

 

[wolf1daddy]

Just found this site. First, apologies for the lack of saw details here, please tell me if I need to get more info before you can help, I don't have the saw here to look at. I considered trying to look through all the posts here, but 53 pages will take me forever and I might miss what I'm looking for anyway.

My dad bought a McCulloch chainsaw mid-1990s. I believe it was 14" (maybe 12"?). It was a lower-cost saw, from Home Depot or something like that. It was NOT an auto oiler, it had the little lever you pumped with your thumb to lube the chain. From memory and pictures online, it looks like maybe a Mini Mac 110.

It ran great all the time. Was last used maybe 10 years ago. The problem was that bar oil leaked out when the saw was stored and the oil tank was empty the next time the saw was used. There was never a problem starting it and the oiler worked fine as long as there was oil in the tank. The oil just leaked and wound up in the bottom of the storage case. So it didn't affect the use of the saw, it was just messy.

I'm going to start using the saw in a month or so. I'm sure I can use it as-is, but I'd like to stop the leak. Any and all help is appreciated! Thanks.

 

[heimannm]

If there is no automatic oiler the only option for leaking are the rubber connector between the oil tank and the bar pad on the crankcase, or the oil tank itself. If in fact it has the automatic oil pump the o-ring at the base of the automatic pump is probably at fault although the rubber connectors and oil tank itself are again possibilities.

You will need to pull the front cover off the saw housing and remove the fuel/oil tank to give it an inspection.

Mark

 

[wolf1daddy]

If there is no automatic oiler the only option for leaking are the rubber connector between the oil tank and the bar pad on the crankcase, or the oil tank itself. If in fact it has the automatic oil pump the o-ring at the base of the automatic pump is probably at fault although the rubber connectors and oil tank itself are again possibilities.

You will need to pull the front cover off the saw housing and remove the fuel/oil tank to give it an inspection.

Mark

Thanks a lot. It definitely is not an automatic oiler. I can remember pushing the wire lever to lube it.

I doubt I will find the owners manual with it. Once I confirm the model, where can I look on the web to find a copy of the manual? And, are there repair manuals and parts lists?

 

[PogoInTheWoods]

Here's a 110 IPL to get you started. It will generally apply to most Mini-Macs. Once you know the actual model number, there may be a more appropriate publication for your particular saw.

Watch this video if you haven't already run across it. It will save you an enormous amount of time and spare you significant frustration!

"A little shake....., that motor comes right out."


​

 

[MacAttack]

Thanks a lot. It definitely is not an automatic oiler. I can remember pushing the wire lever to lube it.

I doubt I will find the owners manual with it. Once I confirm the model, where can I look on the web to find a copy of the manual? And, are there repair manuals and parts lists?

I'm willing to bet it IS an automatic oiler. The small Macs with auto oilers also still have the manual oil lever as a backup.
Is there a small hole with a flathead screw on the front of the housing by the clutch cover?
I use Teflon tape on the rubber T hose that connects the oil tank to the oiler to seal it better and reduce leaking oil.

 

[heimannm]

These was a later saw (100S) with a few serial numbers that did not have the automatic oiler. I don't have one (yet) but I do have the IPL describing it. The connector from the oil tank to the bar is a larger T than the one found on the auto/manual saws.



Mark

 

[MacAttack]

That's very curious that they would have marketed a later version of the Mini Mac with only a manual oiler. The only Mini Mac I have like that is my early Mini Mac 6.

 

[wolf1daddy]

Here's a 110 IPL to get you started. It will generally apply to most Mini-Macs. Once you know the actual model number, there may be a more appropriate publication for your particular saw.

Watch this video if you haven't already run across it. It will save you an enormous amount of time and spare you significant frustration!

"A little shake....., that motor comes right out."


​

Thanks. Hopefully I can get to the saw soon to see which model it is.

 

[wolf1daddy]

I'm willing to bet it IS an automatic oiler. The small Macs with auto oilers also still have the manual oil lever as a backup.
Is there a small hole with a flathead screw on the front of the housing by the clutch cover?
I use Teflon tape on the rubber T hose that connects the oil tank to the oiler to seal it better and reduce leaking oil.

I only have experience with this one saw. I remember pushing the manual oil lever. Can't remember if I did that because it was in the operating manual. I do know the chain seemed to run dry if I didn't pump the lever. I guess I'll find out when I am able to get to the saw. Thanks for the teflon tip.

 

[wolf1daddy]

These was a later saw (100S) with a few serial numbers that did not have the automatic oiler. I don't have one (yet) but I do have the IPL describing it. The connector from the oil tank to the bar is a larger T than the one found on the auto/manual saws.

View attachment 917513

Mark

Hmmm...100S rings a bell, but maybe it's my imagination. Will be interesting to see when I find the saw. I'm fairly confident I knew enough about it back then to know if it was an auto oiler, so I'm also fairly confident it was manual. I know if was a low cost model, purchased to take down one tree.

 

[MacAttack]

I only have experience with this one saw. I remember pushing the manual oil lever. Can't remember if I did that because it was in the operating manual. I do know the chain seemed to run dry if I didn't pump the lever. I guess I'll find out when I am able to get to the saw. Thanks for the teflon tip.

Some pictures will help. If it does have an auto oiler, it's not uncommon for them to get plugged with crud and stop working, or need adjustment or repair.

 

[heimannm]

I had a problem while working on a Power Mac 6 this week and I thought I'd share my experiences. This was a saw that I'd put together from the best parts I had available and gave it to local fellow that has taken up tree removal. It had a bad stumble off idle but I thought it might get better with some use, came back since it didn't.

My first attempt was to take the extended fuel inlet fitting off the MDC carburetor and equip the saw with a Zama instead (ZaMDC???). In order to mate the extended fuel inlet fitting to the carburetor I had to mill the pockets that fit the nibs on the plastic fuel pump body section. The Zama carburetor took care of the running issues but needed to have the longer choke shaft from the MDC to work on the PM6 saw so I did a little more searching and found a NIB MDC which of course solved all the running issues.

Now the problem, the oilers (manual and automatic) worked fine with a full oil tank, but would not work with the tank 1/2 empty or so. I spent literally hours taking everything apart, cleaning, testing, reassembling, testing, and still no success. By trial and error I concluded the oil pick up tube was not sealing properly against the body of the oil tank and the manual oil pump body. If I turned the saw on its side so the pick up tube location was under oil it would pump manually once or twice until the line emptied, then quit again. Finally in desperation I put a #011 o-ring in the counterbore for the oil line and reassembled the whole affair and we had a gusher again.

Keep this in mind when working on the older saws with parts that may have shrunk a bit over the years, the 10 Series saws have a similar situation with a flange on the oil pick up line that has to seal between the oil tank and the manual pump body. The 10 Series have an added issue with varying thicknesses of the flange on the oil pick up tube and thick (phenolic) and thin (aluminum) check valve discs. The thicker flange must be used with the thin disc and the thinner flange with the thick disc or the check valve will not function correctly.

I did not take any photos, but the o-ring goes in the counterbore under the check disc shown as Item 19 below. The flange of the oil pick up line then seals on the o-ring.



Mark

 

[MacAttack]

Nice job Mark.

I'm still no closer to resolving my wide open throttle stumble / surging on my MM25. I stripped it apart again, for the heck of it I timed myself. From fully assembled saw to the engine out and on my bench: 8 minutes flat, haha.

From Pogo's input and my own gut feeling I popped off the flywheel hoping I'd find the points burned or way out of adjustment causing a delayed timing. The points are slightly out of adjustment (max open about .025" instead of the spec .018"), but not the smoking gun I was looking for, and like always the saw has a blazing hot spark when I bench test.

My thoughts are some weird issue with the metering lever in the carb, which was badly bent out of adjustment when I found it, or something going on with the coil. I've read a dying coil CAN act squirrely at higher throttle positions but seem perfect at idle to 1/2 throttle. I have some other Mini Mac coils I can swap to see if it changes. If not, next step will be a full carb swap.

 

[heimannm]

I have had a lot of difficulty with the MDC carburetors lately, it seems to me that the aluminum they used does not age well. I wouldn't mind having a few more Zamas on the shelf so I could just swap them out when there is a problem. I suppose the fact that the Zama carburetors were used later means they are less likely to have corrosion issues.

Mark

 

[MacAttack]

When I disassembled and rebuilt the Zama carb in my Super Pro 40 I immediately felt it was a superior design to the Walbro MDC. It's probably more than just a gut feeling since my SP40 ran good the first time I put together and now I have an MDC that I can't seem to get right, even being cleaned and rebuilt.
My ultrasonic cleaner seems to be the ticket for cleaning tiny passageways in these little carbs, but I want to try a new solution formula that removes tarnish better than the Simple Green that I'm using now.

 

[PogoInTheWoods]

I would not use Simple Green in a USC for carbs. https://simplegreen.com/faqs/15/

SeaFoam in a small plastic container or baggie dropped into a USC full of plain water is a good method/solution for stubborn cases as is just using pure gasoline for the solvent. For a general cleaning solution I use 50/50 PineSol and water with a dash of dish detergent followed by a good rinse in clean water, then gently air dried with my compressor before an exterior spray down of WD-40 and fuel applied to the internals as soon as possible. Near as I can figure, that pretty much covers just about everything I've ever read on the subject. LOL And it actually seems to be very effective without the introduction of caustics to the alloy.

 

[MacAttack]

I would not use Simple Green in a USC for carbs. https://simplegreen.com/faqs/15/

SeaFoam in a small plastic container or baggie dropped into a USC full of plain water is a good method/solution for stubborn cases as is just using pure gasoline for the solvent. For a general cleaning solution I use 50/50 PineSol and water with a dash of dish detergent followed by a good rinse in clean water, then gently air dried with my compressor before an exterior spray down of WD-40 and fuel applied to the internals as soon as possible. Near as I can figure, that pretty much covers just about everything I've ever read on the subject. LOL And it actually seems to be very effective without the introduction of caustics to the alloy.

Thanks for the advice!

I forgot to mention, the type of simple green that i was using is the version that is supposed to be safe for aluminum, it's the simple green HD degreaser. I'll try the seafoam in a baggy.

 

[heimannm]

I have been using some Mr. Clean since I had it on hand. I found that even on the corrosion prone MDC carburetors it does a nice job in the USC without turning them black the way the Purple Power did. I do have some Dawn on hand as well so I'll try adding a little to see what happens.

Have you ever watched a part in the USC when you first switch it on? It is really amazing to see the dirt and scum come floating off.

Mark

 

[MacAttack]

Yep, I love the little plumes of "smoke" that rise up out of the passageways in the USC, haha.
I've used the USC with the Simple Green HD on a few carbs, I had a Chinese carb off of a "Huskee" tiller that was badly gummed up by ethanol gas (tiller was given to me). It would barely run at all, and only with the choke on. After a good disassembly and a session though the USC, the tiller runs perfect.
Anyway.... I have another Mini Mac 30 almost apart to steal the coil, and I'm going adjust the points and swap a different metering lever onto that $#&!!$# MM25 and see if that changes anything...