Late 80's McCulloch 2.0 CID Eager Beaver

[Multifaceted]

My bench top being clear like that is a rare occurrence, typically it's scattered with parts and tools with various projects.

Put the carb and saw back together yesterday morning fired it up without the bar on, and she ran, would respond hesitantly to an open throttle, but before I could grab my screwdriver to adjust the mixing screws, it would slow down and die in idle. Then after she warms up, it seems to not want to start as easily, and dies in idle even faster than before. I'll wait a few minutes and try and, she'll fire right up but still slow and shut off in idle. Nothing changes even with minor intermittent hi/lo adjustments.

Going to have to take it apart again, it seems as if it's not drafting enough fuel, perhaps the fuel line is pinched. It tucks under the carb and coil and snaps in place in the bottom of the housing so to line up with the fuel tank connection.

 

[bpt323]

any luck???
do you have that craptastic tank filter installed ??(looks like a chunk of fabric/cotton stuffed through the hole)
im having issues with mine not being able to get fuel into the carb

 

[Old2stroke]

That lame piece of felt that is stuffed in the outlet port of the fuel tank is really the fuel pickup wick and is meant to hold enough fuel to run the saw if it is tipped in some direction where the fuel runs away from the bottom of the tank. There is no fuel line with a dangler filter to follow the fuel around like in most saws. Some of the old McCulloch such as the early D-44 used this system and it really SUCKS. In addition to being a poor way to supply fuel, that felt can dry out and get hard to the point where it won't flow much fuel. I have often pulled the felt wick out and cut off the front part that gets compressed and hard, then reinstalled it to get better flow.

 

[Multifaceted]

No luck, fellas. I've taken thing apart more times than I care to admit. It'll start up, but stalls quickly like it's not drafting enough fuel. I'll take a look into removing that little felt 'filter' at the bottom of the tank, it's probably stiff as Leather. This thing sat in a dank basement for nearly 25 years unused...

 

[dynodave]

These have a walbro or zama carb. Zama does not make the kit any more. Supposidly tillitson does make an aftermarket kit for the zama.
You can still get the walbro diaphragm/gasket kit but not the full rebuild kit.
If your saw had E-10 mix in it..it is probably dead and needs a carb kit especially the regulator diaphragm.
Maybe some guys have more experience with them than I.

 

[Old2stroke]

To verify if the fuel supply from the tank is an issue, with the tank removed just half fill it with fuel and see how fast it dribbles out of the outlet port.

 

[Multifaceted]

These have a walbro or zama carb. Zama does not make the kit any more. Supposidly tillitson does make an aftermarket kit for the zama.
You can still get the walbro diaphragm/gasket kit but not the full rebuild kit.
If your saw had E-10 mix in it..it is probably dead and needs a carb kit especially the regulator diaphragm.
Maybe some guys have more experience with them than I.

I have or used the diaphragm kit when I cleaned the carb, replaced the diaphragms, gaskets, metering lever, spring, and needle, along with new fuel line, air filter and spark plug.

 

[Multifaceted]

To verify if the fuel supply from the tank is an issue, with the tank removed just half fill it with fuel and see how fast it dribbles out of the outlet port.

I'll give that a try... Never thought of that, yet it sounds about as simple as it could get.

 

[Multifaceted]

The felt wick filter thing seemed to be flowing some (a slow drip) but I still pulled it out and cut about an 1/8" of the end. Now it leaks from the fuel pickup outlet when I add a little gas mix the the reservoir. While I had the dang thing apart, I disassembled the carb again to make sure nothing was amiss. Sure as you-know-what I noticed that the metering lever arm was not flush with the top of the gasket seat, so I gently bent the arm downward so it sits almost flush, just below the seat. It got late last night so that's as far as I got, it's still disassembled on my workbench mis en place....

Will update further if anyone is still interested. Again, it'll start up cold and scream momentarily, but runs out when I let it back down to idle.

To recap: Carb has new gaskets, metering needle, arm and spring. Welch plug was not removed (gasket kit did not include a replacement plug). New fuel line, spark plug, and air filter. Hi/Lo jets were cleaned and reset to default position. Last time this ever had fuel in the tank before I got it was maybe 1988 so I do not suspect any ethanol related issues.

 

[Multifaceted]

Update: the old saw runs and cuts! Finally got the time to put the old girl back together this afternoon. Seems as if trimming the felt fuel filter and correcting the metering lever solved the problem. I did have to start with a little squirt of starting fluid, but it had no problem starting up again warm or cold after about 45 minutes after realizing that I didn't have the bar oil take inlet alligned with the reservoir... Then leaked oil all over my bench and inside the housing...

Anyway, got it all back together and tuned the carb in wood. Cuts pretty good, but will need to slight adjustments later during use.

Very happy to have this running again, it'll be nice to have a little top handle for limbing the small stuff, and this was my late father's saw for when he did a brief stint of tree work in the late 80's

 

[heimannm]

Just a few points -

The carburetor with plastic disc is the Zama (M1-M7), kits are available just about anywhere you look.

The Walbro carburetor is the MDC and kits are also readily available. The Walbro carburetors have a very feeble check valve and there were kits available to replace them but getting them apart to replace the little disc is more challenging that working on a Mini Mac. By the way, except for the Mini Mac 6 (the first release) all models have a removable starter so taking one apart is really a 15-20 minute job. Disconnecting and reconnecting the throttle is the greatest challenge.

The Zama has the plastic disc between the metering diaphragm and the metering lever, the Walbro has a metal tit riveted in place to bear on the metering lever. Neither had a fork like you find on the Walbro SDC and others. The gaskets and diaphragms are virtually interchangeable between the two, but the metering diaphragms are quite different so the parts will not interchange. Believe me, I have really, really tried to switch the MDC into the Zama and you can't make it work.

Always check the metering lever height before assembling the carburetor (flush with the base in the carburetor), a pressure test before reassembling the saw is always a good idea and can save a lot of grief.

The impulse signal comes from the crankcase through the insulator where the carburetor mounts so there is no additional impulse line. A damaged gasket could potentially block the port but in general it is a very reliable system. The plastic insulators over the screws help position the gasket and carburetor to make sure everything is properly aligned when you put it together.

The Mini Mac needs at least 100 PSI compression to run at all. 120 to 140 PSI will run better.

There is no fuel tank vent, evidently they expected the fuel would heat up enough and expand to avoid any excess vacuum issues.

The screen on the outside of the carburetor is the atmospheric vent to the metering diaphragm. Most carburetors have a small hole with no protection so it is not uncommon to find a lot of sawdust dust accumulated on the metering diaphragm; a bit less of an issue on the PM6 and Mini Mac saws with the screen.

Older models did not have the screen in the fuel tank, just a felt filter/wick. Old 2 stroke doesn't think much of the approach but it does provide a significant amount of filter area and also works to absorb any water that might be in the fuel. The only time it is every a problem is when the saw is left for a long time with fuel in the tank that evaporates and leaves a heavy coating of varnish in/on the filter media.

The o-ring in the oiler is an 022 (I think I remember correctly), never a bad idea to replace the o-ring if there is any question to minimize the possibility of bar oil leaking into the crankcase. If the automatic oil pump is badly worn, it may still leak into the crankcase producing a near hydro-lock condition when you try to start the saw. Easiest fix is to leave the oil tank mostly empty to minimize oil leaking into the crankcase. Also a good idea to make sure the oil pumps (manual and automatic) both work before assembling the saw. Work the piston in the automatic pump with your finger and you can watch the oil go down in the inlet (connects to the tank through the "T" fitting) and out the discharge hole. There is only one check valve in the system and it is internal in the automatic pump and is not serviceable. You can replace the manual oiler piston but they rarely fail.

It is also a good idea to pressure/vacuum test the crankcase to make sure there is no leaking seal. It is not uncommon for folks to use these in the grass or weeds so a few wraps around the PTO side crankshaft can take a seal out in a hurry.

At 2 In³ the engine is quite capable, but the handle design makes them somewhat awkward to use for an extended period, I find the little finger on my right hand gets very hot from "counter balancing" against the top of the case when sawing.

My latest Mini Mac project...



The Eager Beaver 2.1 is a 300 Series saw, different animal altogether.

Mark

 

[Multifaceted]

Just a few points -

The carburetor with plastic disc is the Zama (M1-M7), kits are available just about anywhere you look.

The Walbro carburetor is the MDC and kits are also readily available. The Walbro carburetors have a very feeble check valve and there were kits available to replace them but getting them apart to replace the little disc is more challenging that working on a Mini Mac. By the way, except for the Mini Mac 6 (the first release) all models have a removable starter so taking one apart is really a 15-20 job. Disconnecting and reconnecting the throttle is the greatest challenge.

The Zama has the plastic disc between the metering diaphragm and the metering lever, the Walbro has a metal tit riveted in place to bear on the metering lever. Neither had a fork like you find on the Walbro SDC and others. The gaskets and diaphragms are virtually interchangeable between the two, but the metering diaphragms are quite different so the parts will not interchange. Believe me, I have really, really tried to switch the MDC into the Zama and you can't make it work.

Always check the metering lever height before assembling the carburetor (flush with the base in the carburetor), a pressure test before reassembling the saw is always a good idea and can save a lot of grief.

The impulse signal comes from the crankcase through the insulator where the carburetor mounts so there is no additional impulse line. A damaged gasket could potentially block the port but in general it is a very reliable system. The plastic insulators help position the gasket and carburetor to make sure everything is properly aligned when you put it together.

The Mini Mac needs at least 100 PSI compression to run at all. 120 to 140 PSI will run better.

There is no fuel tank vent, evidently they expected the fuel would heat up enough and expand to avoid any excess vacuum issues.

The screen on the outside of the carburetor is the atmospheric vent to the metering diaphragm. Most carburetors have a small hole with no protection so it is not uncommon to find a lot of sawdust dust accumulated on the metering diaphragm; a bit less of an issue on the PM6 and Mini Mac saws with the screen.

Older models did not have the screen in the fuel tank, just a felt filter/wick. Old 2 stroke doesn't think much of the approach but it does provide a significant amount of filter area and also works to absorb any water that might be in the fuel. The only time it is every a problem is when the saw is left for a long time with fuel in the tank that evaporates and leaves a heavy coating of varnish in/on the filter media.

The o-ring in the oiler is an 022 (I think I remember correctly), never a bad idea to replace the o-ring if there is any question to minimize the possibility of bar oil leaking into the crankcase. If the automatic oil pump is badly worn, it may still leak into the crankcase producing a near hydro-lock condition when you try to start the saw. Easiest fix is to leave the oil tank mostly empty to minimize oil leaking into the crankcase. Also a good idea to make sure the oil pumps (manual and automatic) both work before assembling the saw. Work the piston in the automatic pump with your finger and you can watch the oil go down in the inlet (connects to the tank through the "T" fitting) and out the discharge hole. There is only one check valve in the system and it is internal in the automatic pump and is not serviceable. You can replace the manual oiler piston but they rarely fail.

It is also a good idea to pressure/vacuum test the crankcase to make sure there is no leaking seal. It is not uncommon for folks to use these in the grass or weeds so a few wraps around the PTO side crankshaft can take a seal out in a hurry.

At 2 In³ the engine is quite capable, but the handle design makes them somewhat awkward to use for an extended period, I find the little finger on my right hand gets very hot from "counter balancing" against the top of the case when sawing.

My latest Mini Mac project...

View attachment 664366

The Eager Beaver 2.1 is a 300 Series saw, different animal altogether.

Mark

Absolutely incredible write up, thank you for taking the time to respond with this knowledge. I certainly learned a lot over the past 6 months working on this saw, but these points are a great reference for future maintenance. That MiniMac 2.1 definitely is a different animal, instead of Eager Braver it's a Silver Eagle. Pretty cool.

I agree, this saw is a little awkward to use, has a lot of forward bias, not balanced at all.

 

[grizz55chev]

Just a few points -

The carburetor with plastic disc is the Zama (M1-M7), kits are available just about anywhere you look.

The Walbro carburetor is the MDC and kits are also readily available. The Walbro carburetors have a very feeble check valve and there were kits available to replace them but getting them apart to replace the little disc is more challenging that working on a Mini Mac. By the way, except for the Mini Mac 6 (the first release) all models have a removable starter so taking one apart is really a 15-20 job. Disconnecting and reconnecting the throttle is the greatest challenge.

The Zama has the plastic disc between the metering diaphragm and the metering lever, the Walbro has a metal tit riveted in place to bear on the metering lever. Neither had a fork like you find on the Walbro SDC and others. The gaskets and diaphragms are virtually interchangeable between the two, but the metering diaphragms are quite different so the parts will not interchange. Believe me, I have really, really tried to switch the MDC into the Zama and you can't make it work.

Always check the metering lever height before assembling the carburetor (flush with the base in the carburetor), a pressure test before reassembling the saw is always a good idea and can save a lot of grief.

The impulse signal comes from the crankcase through the insulator where the carburetor mounts so there is no additional impulse line. A damaged gasket could potentially block the port but in general it is a very reliable system. The plastic insulators help position the gasket and carburetor to make sure everything is properly aligned when you put it together.

The Mini Mac needs at least 100 PSI compression to run at all. 120 to 140 PSI will run better.

There is no fuel tank vent, evidently they expected the fuel would heat up enough and expand to avoid any excess vacuum issues.

The screen on the outside of the carburetor is the atmospheric vent to the metering diaphragm. Most carburetors have a small hole with no protection so it is not uncommon to find a lot of sawdust dust accumulated on the metering diaphragm; a bit less of an issue on the PM6 and Mini Mac saws with the screen.

Older models did not have the screen in the fuel tank, just a felt filter/wick. Old 2 stroke doesn't think much of the approach but it does provide a significant amount of filter area and also works to absorb any water that might be in the fuel. The only time it is every a problem is when the saw is left for a long time with fuel in the tank that evaporates and leaves a heavy coating of varnish in/on the filter media.

The o-ring in the oiler is an 022 (I think I remember correctly), never a bad idea to replace the o-ring if there is any question to minimize the possibility of bar oil leaking into the crankcase. If the automatic oil pump is badly worn, it may still leak into the crankcase producing a near hydro-lock condition when you try to start the saw. Easiest fix is to leave the oil tank mostly empty to minimize oil leaking into the crankcase. Also a good idea to make sure the oil pumps (manual and automatic) both work before assembling the saw. Work the piston in the automatic pump with your finger and you can watch the oil go down in the inlet (connects to the tank through the "T" fitting) and out the discharge hole. There is only one check valve in the system and it is internal in the automatic pump and is not serviceable. You can replace the manual oiler piston but they rarely fail.

It is also a good idea to pressure/vacuum test the crankcase to make sure there is no leaking seal. It is not uncommon for folks to use these in the grass or weeds so a few wraps around the PTO side crankshaft can take a seal out in a hurry.

At 2 In³ the engine is quite capable, but the handle design makes them somewhat awkward to use for an extended period, I find the little finger on my right hand gets very hot from "counter balancing" against the top of the case when sawing.

My latest Mini Mac project...

View attachment 664366

The Eager Beaver 2.1 is a 300 Series saw, different animal altogether.

Mark

Bravo, sir, Bravo! I’ve worked on a few of these, with minimal success. Could have used this post to increase my probability of hearing the little bastards run properly?

 

[Multifaceted]

Bravo, sir, Bravo! I’ve worked on a few of these, with minimal success. Could have used this post to increase my probability of hearing the little bastards run properly?

Agreed, this is akin to a MiniMac Rosetta Stone.

 

[grizz55chev]

I’ve spent WAY more time on these little saws than I care to admit, now I just shake my head and say no when I see one. Same thing for weed eaters, just go buy a new one and throw that pita in the trash! If a nice, clean specimen shows up, I’ll give it one try , then place it in the collection or give it back to the owner, weed eaters can bite me!

 

[heimannm]

That Silver Eagle 2014 is actually a Mini Mac not much different from your Eager Beaver, the 2.1 is based on the 300 Series saws.

Mark

 

[Multifaceted]

I’ve spent WAY more time on these little saws than I care to admit, now I just shake my head and say no when I see one. Same thing for weed eaters, just go buy a new one and throw that pita in the trash! If a nice, clean specimen shows up, I’ll give it one try , then place it in the collection or give it back to the owner, weed eaters can bite me!

I hear ya, brother. I have taken this little thing apart and back together probably 7 or 8 times since January. The good thing is that I'm pretty quick at it now. I had no real need for it, only that it was my old man's. Rather than throw it out, I figured I'd try to get running again.

That Silver Eagle 2014 is actually a Mini Mac not much different from your Eager Beaver, the 2.1 is based on the 300 Series saws.

Mark

Very cool, do you mostly work on McCulloch saws for work or as a hobby?

 

[Old2stroke]

Excellent post by Multifaceted !!
Please don't throw stones at me but I have committed the sin of removing the chain brakes from my "fleet" of Mini Mac 110's, except for one that I keep as a loner and on that one I cut off most of the left part of the handle and the pivot part down by the recoil starter. Brake still works and maybe gives the user some sense of safety. My thinking is I only use these saws with one hand which makes the chain brake release useless, so why not get rid of the ugly damn thing and make it easier to get the clutch side cover off and save a bit of weight at the same time?

 

[heimannm]

There are early versions of the brake on the Mini Mac with a flag at the top only, but later they went with the "full wrap" brake design to insure you would activate it no matter where you bumped the saw in a troubling situation. The 300 and 600 Series saws are the same way. They are ugly and add a few ounces but do lend a small safety factor.



This is a Power Mac (PM) 6 saw but there is a similar brake handle on early brake equipped Mini Mac saws.



Believe it or not, I do this for pleasure as a hobby. I will work on other peoples saws including Mini Macs but that is not my focus or goal.

Mark

 

[Beetlejuice]

I got a kick out of the oil leaking out all over the work bench.. My 2x4 bench will never rust also..