McCulloch MAC140 woes

[TrogL]

I wanted a small chainsaw that I could use in the yard and take camping and found a MAC 140 in a pawnshop. The salesguy gassed it up and ran it a few times and it worked perfectly for him so I took it home.

It hasn't worked right since.

I haven't been able to find a manual online so I'm kind of working in the dark. I'm not all that familiar with two-stroke engines but I've been able to get some advice.

I'm using a 25:1 fuel mixture using regular unleaded gas and Canadian Tire chainsaw oil. I measured carefully using plastic measuring cups. I'm using Canadian Tire chain oil but I've got the clutch out so that's not an issue.

Here's a picture.

It's kind of hard to see the three carburator screws. They are, from top to bottom; idle (and idle lock), lo, hi. The control on the left is the choke and I have to assume the big black button on the right is the primer. The chain oil pump (I assume) is the wire on the T-handle. I choke, pull a few times and it starts and I take the choke off. It runs for about 5 seconds, putting out grey smoke and then dies. The tabletop where I've been running it is soaked with black sludge. When I take the spark plug out, it's wet and black. I found the air filter (left side behind the pull and cleaned it). I haven't figured out how to get the thing apart to get at the fuel filter (which I suspect is the problem). The spark plug looks fine (other than being dirty). No pitting, bending or discoloration. I was gonna replace it anyway but Canadian Tire didn't stock one.

I've tried every setting of the idle screw, lo and hi that I can think of. I've had it running for as long as a minute (but not lately).

So, three questions:

1. Where is the fuel filter and how do I get at it?

2. How do I set the three carburator screws?

3. What else could be wrong?

 

[Lawn Masters]

The fuel filter is a PITA on this model, because its sort of pressed into the gas tank. I hate it, but these saws are rather nice for me. I've got at least one of em.

 

[TrogL]

OK, so how do you get at it?

The fuel filter is a PITA on this model, because its sort of pressed into the gas tank. I hate it, but these saws are rather nice for me. I've got at least one of em.

There's three bolts on the front that look like they take off the front plate, but the big choke handle is in the way. Does it come off as well or is it attached to the front plate?

 

[Lawn Masters]

I assume you mean the chainbrake handle right? that is attached to the clutch cover, and the front cover, you have to remove the bolt from the clutch cover first, then take that off, and swing the handle forward, then when its at a certain point it will slide to the left and off. then you can remove the front cover with ease. I just alter the brake handle a little so I can keep it on, but not have to remove it everytime I remove the front cover.

 

[HiOctane]

Adjustment should be roughly one turn each( Lo-Hi).Looks like you gonna have to clean at least the carb probably,THATS a pain in the a$$ to reach.The big black buttton on the right is an automatic sharpener for the chain.You push the button and the stone touch the chain to sharpen assuming you have the right type of chain.

 

[ozflea]

After removing the chainbrake lever and clutch cover, you find two metal threads or screws holding in place the fuel tank cover remove same and as the cover comes away the manual oiler lever will be loose for removal as well.
With the cover off the plastic fuel tank is easy to pry out of the saw body but be aware that at the lower rear of the tank is a plastic hose fitting for the fuel line, after removal of the tank remove this plastic fitting and inserted behind it is the fuel filter, the filter is square and a few inches long.

Have fun their not a hard job just fiddly.

Mc Bob.

 

[TrogL]

Any idea where to buy a filter?

Got it all taken apart finally. The fuel filter was basically a solid mass. I tore some of the front part off it and it helped a little bit, but it still won't run more than 10 seconds at a time, meaning either it's still not getting gas or it's flooding.

I've hit all the stores in the area and can't find one that sells fuel filters at ALL never mind one for this particular chainsaw.

I might try improvising one out of the fuel filter for a lawnmower.

 

[TrogL]

Need a replacement chain

The chain looks pretty worn so I may as well pony up for a new one (by the time this is finished I'll have run up the price of a new saw - oh, well).

Canadian Tire sells replacement chains for every saw imaginable except this one. They've got chains for the MAC120 and 130, just not the 140.

Anybody now the number of links, length and whatever else I need to find a replacement?

 

[Lawn Masters]

the 140 is the exact same thing as the 120 and 130. what you need to do, is a PITA but will probably work, is rebuild the carb, and clean it really good.

 

[Al Smith]

I have one of these little pain in backsides saws.[Mac 120]You have to nearly field strip them to get to anything.Believe it or not,they were used as arborists saws,at one time.They were cheap,but a person could get several years out of them,then just replace them,rather than repair.In good running condition,they are really not that bad of a saw,for what they are.You can get the carb kits through msgsupply.com,cheap.It's either a Zama-M1-M7 or a Walbro MDC.The key to working on these little gems is patience,lots of it.

 

[Lawn Masters]

what Al said. I hae the patience to work on these little saws. anyone that doesnt have that kind of patience and wants to ditch theirs, send it to me. I want as many of em as I can get. they're just that much fun for me.