Stihl 042AV Project saw

[LB6259]

Recently bought this saw close to a month ago, just for fun.

Preliminaries:
-has spark
-has good compression
-piston shows no signs of scoring to the best I can tell. (Picture attached) might have to clean the port out at a minimum.

Now the bad:

It's missing the chainbrake assembly. This is probably one of the dumbest ideas I've come up with, but I decided "why not try a 038 brake assembly and see if that'll work?"(Pictures of this stupid idea also attached).

I can't for the life of me figure out how the clutch/sprocket is supposed to be installed. I bought a service manual thats supposed to show up at some point but I can't get it to sit flush on the crankshaft (possible that it's the wrong one? I'll have to get pictures of it next time I yank it out of the shed. Also may be missing some pieces that go to it, I know I definitely need a bearing at the most, I do have an assortment of washers that came with it along with what I'm guessing is a sprocket).

Want to note that from what I've read up on this particular saw, it has a mixed reputation, and I'm aware parts are NLA or next to impossible to find. At most I just want to try my hand at getting this somewhat usable before I go messing with another project saw (I have plenty of others laying around, listed them in my introduction post)

 

[Woodslasher]

I rebuilt one of these from the ground up with no saw-wrenching experience and only an ipl to help me, so I'm pretty sure anybody can do it. Here's a copy of an 042 ipl, it should do a pretty good job of illustrating how it goes back together.

 

[LB6259]

Awesome thank you so much. Definitely going to be referring back to it so I can double check myself.

 

[LB6259]

Ok, looking at the ipl, I'm even more confused.

It's showing that the clutch should be able to be threaded onto the crankshaft... somehow. Yet looking at the crankshaft there aren't any threads I can see. The clutch portion will not slide all the way down flush on this piece on the lower end of the shaft.. I'm not sure what it even is as I don't see it anywhere on the ipl, unless it's a bearing.

 

[Woodslasher]

That's what I thought I saw, see if you can pry/pull/unscrew that sleeve piece. There should be threads underneath it for you to screw the clutch onto, like the ones of the crank below:

 

[SteveSr]

Ok, looking at the ipl, I'm even more confused.

It's showing that the clutch should be able to be threaded onto the crankshaft... somehow. Yet looking at the crankshaft there aren't any threads I can see. The clutch portion will not slide all the way down flush on this piece on the lower end of the shaft.. I'm not sure what it even is as I don't see it anywhere on the ipl, unless it's a bearing.

This saw appears to be a VERY early 024 complete with the 028 style of oil pump.

That spline thingy (technical term) on the end of the crank likely drives the clutch. The spline is likely threaded onto the crankshaft (left hand thread). Looks like you'll need a special tool to remove it.

 

[LB6259]

This saw appears to be a VERY early 024 complete with the 028 style of oil pump.

That spline thingy (technical term) on the end of the crank likely drives the clutch. The spline is likely threaded onto the crankshaft (left hand thread). Looks like you'll need a special tool to remove it

Looking at the 024, I can see the spline piece and agree that I may need to look into getting a tool to remove it. However, this saw has the fuel and oil tanks on the same side instead of opposite one another, as well as the 042 badging. Unless somebody swapped covers.

 

[SteveSr]

Looking at the 024, I can see the spline piece and agree that I may need to look into getting a tool to remove it. However, this saw has the fuel and oil tanks on the same side instead of opposite one another, as well as the 042 badging. Unless somebody swapped covers.

That saw is NOT an 024!

 

[LB6259]

That saw is NOT an 024!

No no, I'm aware it's an 042. I might've gotten confused with what you were trying to say.

 

[stihltech]

I am looking at the IPL and your picture of the crank in the saw. I THINK what you have is the remnants of a declutching chain brake. These were popular on many STIHL models in the 80s. There was a serrated sleeve that screwed on to the crank through the clutch.. The clutch spun this sleeve. There was a plate on the case that would push the clutch into the serration to lock the clutch to the crank.
It has been a LONG time since I have seen one of these setups. I don't know if I have an old paper or fiche IPL that would show it. This can be converted to a regular clutch as most were. The flat springs would get weak and not engage the clutch. Those springs are out of the system many moons ago.
Keep thinking I might resurrect the 2 or 3 042s or 048s ih ave in the deadpile. Case gaskets coming out of place were #1 repair.

 

[LB6259]

That's what I'm wondering too, the clutch that came with this is missing a bunch of different parts and the bearing(s) but I did find a complete one-with bearings- that I'm currently waiting on.

As far as the case gaskets, how difficult is it to change one of these courses in the event this needs it?

 

[stihltech]

You will need to split the case to replace the gasket. If you remove the muffler and look between the tank and the case, you may see the broken gasket hanging down and/or missing. Pretty common repair.
Search for splitting a chainsaw case on here. There are many posts showing how.

 

[LB6259]

Definitely keeping that in mind. Once I get a free day to tear into the saw again I'll take a look and see if the gasket's shot.

 

[bulletpruf]

Neat old saw, but man, they are hard to find parts for. I've had one or two of these and some stuff was super difficult to source. Good luck with it.

FYI - on the case and other gaskets, you can easily make these. Just takes an exacto knife, some bulk gasket material, and a bit of patience.

 

[LB6259]

Well... between being slammed at work and working on other projects, I've managed to get the new clutch installed, but the oil pump gear that attaches to the sprocket is slightly too small. Found a genuine Stihl one that I'm waiting for, hopefully that one works.

 

[LB6259]

Back at it again.

Bought the wrong clutch gear, correct one (#11176421503) showed up yesterday. Slowly starting to put this back together, all I need now is a bar/chain.

 

[LB6259]

It's been a bit since I've been on here, but I have an update.

I gave up on the chainbrake installation for now. I DID manage to find a (used) chainbrake setup with some hardware parts on eBay, but I'm still having trouble figuring out how to put it together. Besides that setback, I did get the saw running. Revs up fine but it surges at idle, longest I've had it running with this issue is 15 minutes before it dies. My guess is there's an air leak somewhere or the idle circuit in the carburetor is messed up. But overall, given the rarity of this saw and the parts being nearly impossible to find, it's fairly nice to use.

The only other issue I'm having besides idle is the recoil doesn't grab onto the flywheel all of the time, I'm not entirely sure what is causing it. But for now, this is the biggest saw that I own right now that runs, and I'm satisfied.

 

[Dean-O]

I am looking at the IPL and your picture of the crank in the saw. I THINK what you have is the remnants of a declutching chain brake. These were popular on many STIHL models in the 80s. There was a serrated sleeve that screwed on to the crank through the clutch.. The clutch spun this sleeve. There was a plate on the case that would push the clutch into the serration to lock the clutch to the crank.
It has been a LONG time since I have seen one of these setups. I don't know if I have an old paper or fiche IPL that would show it. This can be converted to a regular clutch as most were. The flat springs would get weak and not engage the clutch. Those springs are out of the system many moons ago.
Keep thinking I might resurrect the 2 or 3 042s or 048s ih ave in the deadpile. Case gaskets coming out of place were #1 repair.

Good call! Here is my 045 with that clutch setup.

 

[Woodslasher]

It's been a bit since I've been on here, but I have an update.

I gave up on the chainbrake installation for now. I DID manage to find a (used) chainbrake setup with some hardware parts on eBay, but I'm still having trouble figuring out how to put it together. Besides that setback, I did get the saw running. Revs up fine but it surges at idle, longest I've had it running with this issue is 15 minutes before it dies. My guess is there's an air leak somewhere or the idle circuit in the carburetor is messed up. But overall, given the rarity of this saw and the parts being nearly impossible to find, it's fairly nice to use.

The only other issue I'm having besides idle is the recoil doesn't grab onto the flywheel all of the time, I'm not entirely sure what is causing it. But for now, this is the biggest saw that I own right now that runs, and I'm satisfied.

15 minutes sounds like bad coil, saw gets hot and coil dies. Saw cools down, coil works again, saw starts, repeat the process. The slipping recoil is probably worn pawls, a worn drum, or a worn spring. Maybe the flywheel's worn down too but I kinda doubt it.

 

[stihltech]

Dis the saw get pressure and vacuum tested? Fuel tank vent open? When it quits, immediately test for spark.