McCulloch eager beaver 2.0

[Elliots]

Hello everyone, hope someone might be able to help. I have an old chainsaw that always ran. It is a small saw, but for things around the house it has been great. Last week I went out to cut a few branches before leaves started to appear in an overgrown area of the yard. New spark plug, new gas and oil and the thing fired right up. The second day i used it I was cutting, and then all of a sudden the blade started to slip or slowly move no matter how much I pulled the trigger until it finally seemed to lock up. After doing some reading it seems that it may be the clutch? The engine was working just fine. Here are a few pictures of the clutch after I took it off. It does have a few grooves, but I really have no idea if it is bad. Any thoughts would help. Thanks. Elliot

 

[Michael E]

Your sprocket is worn. That's the only thing I can tell from the pictures, because you didn't show any of the mating surfaces (outside of clutch, inside of drum).

Can you elaborate on the problem? What does "started to slip or slowly move" mean? Does it move too easy or not easy enough?

When you take off bar and chain, does the engine work normally? Does it rev up? If the bar is not attached to the saw and you move the chain through the groove of the bar, does it slide easily? If the bar is mounted (engine turned off), does the chain slide easily in the grove?

Sometimes there is simply dirt or sawdust in the groove and blocks the chain.

 

[Elliots]

Thanks for your reply. "Move slowly".... as I would squeeze the throttle the chain would turn on the bar, but very slowly until it finally stopped moving at all. After it stopped the chain actually wouldn't move at all. The engine seemed to rev. fine before that. The saw is dirty and I need to clean it now that I have the clutch off. I have not attempted to start it again without the bar and chain or clutch. Here are the additional pictures I believe you mentioned?

I can attempt to start it without the clutch. Then if you believe the clutch is ok, I can put it back together and try again, then add the bar and chain, unless you think a new sprocket is warranted? The other thought I had is perhaps it is not getting lubricant, which is full. I need to find where the oil lubricates the bar? Perhaps that is clogged? Thank you.

 

[Rocker59]

When you took the clutch nut off, was it easy to get off? Did the clutch just fall off? Sounds like the clutch was pinning on the crankshaft. Hard to tell from the picture, but it looks like wear on the shaft taper.

 

[MacAttack]

It's hard to imagine how the chain can just stop moving unless either the sprocket / clutch was completely toast, or if the chain was so over-tightened it was seizing to the bar.

 

[Elliots]

Thanks all. Don't know if this helps but here are pics of the crankshaft. The clutch pulled right off when I took the bolt off. As for the chain, it was not that tight. Always make sure there is a bit of pull in it. I would squeeze the throttle and the engine would rev, higher and higher as I squeezed. The chain would slowly spin, then in the very end the whole thing stopped. At that point the chain was tight and I was unable to move it by hand, there was also a bit of smoke. That with the tight chain was why I thought maybe no oil and it locked up. Although, I guess that wouldn't explain the chain barely moving as the motor revved higher. Just for an fyi, without the bar or clutch, I did start the saw and the motor was fine. Started like a champion, revved up. Crankshaft was turning. This has been a great little saw for me the past few years. Thanks for the help all!

 

[MacAttack]

With the engine off, if the chain is adjusted correctly it shouldn't be hanging slack off the bar but you should be able to easily move the chain by hand without binding.

It still sounds to me like you're running chain too tight. Unless you have a pinched bar that's keeping the chain from turning.

 

[Elliots]

I was able to pull the chain away from the bar a bit and it moved by hand easily before i started it. Where does the oil come out for the chain and the bar? Also, can anyone tell if those sprockets are bad? Since it will start, I thought I would clean it and put the clutch back together and see if it works with the bar and chain. The crankshaft is spinning.. would that mean that the crankshaft is "good"? What about the "Taper"? Thanks again everyone.

 

[MacAttack]

Just for the heck of it...loosen the chain so that it actually hangs off the bottom of the bar by 1/16 of an inch and try running your saw.

If you are "able to pull the chain off the bar" but it requires any more than the slightest amount of effort, the chain is on the tight side.

 

[Michael E]

If the engine is revving, but the chain barely moves, usually the clutch is slipping. That doesn't mean that the clutch is bad, just that the friction that mates clutch and drum is not high enough to move the chain. There are a few reasons that can cause this: The chain might be too tight. The bar might be warped or pinched. Chain drive links might be bent or mushroomed. Bar nose sprocket might be seized. Et cetera. Just check if the chain is moving.

When you are reassembling the clutch: The drive sprocket on the clutch drum is worn, but not to the point where it would cause this problem. It's at the end end of its life span, buy a new clutch cover soon (only if you get the saw running again). Inside the clutch cover shaft opening is a bearing. take it out, inspect it and grease it before assembly.

The bar oil comes out of a groove in the crank case, right where the bar mounts to the crank case, 1/2" above the stud. If you run the saw without the bar, oil should visibly come out of there. The oil pump is driven by the impulse and is a weak spot of those saws. Taking it out and cleaning it has worked for me in the past. Also, make sure to keep the little hole in clean that leads the oil into the groove of the bar.

 

[MacAttack]

I circled where the bar oil comes out of the bar mounting pad:

 

[Elliots]

Thanks everyone, let me give this a try.

 

[Rocker59]

My mistake, I interpreted Eager Beaver 2.0 as the Mac 100 series saw. The 1635 type saw did not have a taper on the PTO side of the crank. The clutch is held on place by the outer disc and a flange nut. If the nut is not to the correct torque, the clutch can slip. Same with the flywheel on the other side. See attached specs.

 

[Michael E]

My mistake, I interpreted Eager Beaver 2.0 as the Mac 100 series saw.

So did I. Had to read everything I wrote to check if it still applies. I think it does

 

[Doug]

My guess is that the clutch was lose on the crank, and depending on how long it has run that way, the crank might now be worn to the point where the clutch fit-up is no longer snug. Back-in-the-day the field fix for this sort of thing (and I've never done this on a chain saw, but did it many times on bigger stuff) was to center-punch the shaft and then assemble with Loctite Bearing Mount. Often that snugged it up enough to put it back in service. At least for a while. How much center-punch is important. Too little does not accomplish the goal. Looking for a tap-it-on-with-a-hammer fit. Too much center punching and you have to get a bigger hammer and drive it on hard. And that's still do-able BUT you better back-up the other end of the crank so you don't damage the bearings.
Again, that's just a Field Fix. You do what you can, with what you got, to get it going again.
And often it would last a lot longer than you would think

 

[LawrenceK]

Remove the cover plate, bar and chain, sprocket and sprocket bearing (little cage bearing in sprocket), Blow the snot out of everything if you have an air compressor. If not, clean it all up some other way with a brush and shop vac or a couple of cans of plastic-safe brake cleaner. replace the sprocket bearing if its shot or grease it if it's in good shape, clean out the groove on your bar from front to back with a small thin flat screwdriver, and the oil passages (holes) on either side of the bar, install a new sprocket and put it all back together. Tighten your chain until it just touches the bottom of the bar with no sag to it. Start it up and see if your problem is solved. If not, then listen to these other guys. They have a pretty good handle on this stuff. By the way, make sure you get the right sprocket if you replace it. Yours doesn't look horrible, but bad enough to start binding. Your clutch looks fine from the pics.