My Stihl 028AV Wood Boss Rebuild

[jgrady1982]

Hello,

I picked up this saw about a week ago in non-running condition. Today I started to tear it apart and see why. This is my third Stihl, I also have a MS250, and then a 009L that I bought off of craigslist last year for $50.

I removed the side bar cover and took off the plastic cover that covers the drive assembly. I was able to remove the drive sprocket and then I stopped when I got to the clutch. I stopped here becuase the crankshaft that it is attached to will moved up and down when I move it with my hand. Is this a broken crankshaft? Or a bad bearing?

I have to try and remove the clutch and then the flywheel later this week. So once I get those guys off it should make the diagnosis much easier. Also, how much of a pain is it to split these cases? I think I saw a thread here of a guy using a modified piece of angle iron to make a case splitter???

Here are the pics: The sharpener stand I made last weekend out of 1/8" steel plate and my Miller Mig 130...set all the way up! There are two bolts with wing nuts that bolt this to my bench, I did not want to sit while I gring my chains, so I made this guy to get them up near my eye level. I used glossy black rust-o-leum paint over a coat of primer. There are 4 triangle braces on the bottom and then one of the backside of the grinder on the top.

I am draining the bar oil into my oil catch pan overnight

Here is my sharpener stand

 

[jgrady1982]

Bump

 

[MnSam]

Nice set up, and good saw to resurrect! A couple questions though. I usually try to diagnose as much as I can before tearing it apart, as in: compression, spark, fuel supply. Perhaps you did but just didn't mention it. Also when you say the crank moves up and down by hand, how much and what direction exactly are you talking? Along the length of the crank, or wobbly about it's axis? At any rate it sounds like you'll need bearings.

 

[bcorradi]

It is a bad bearing so you'll need to split the case as you probably already know. There are a few threads on here where people have made their own tools and successfully split their case. I own the stihl tools, but they aren't very economical if your just going to buy them for personal use.

Nice looking saw grinder stand.

 

[jgrady1982]

Thank you

Cool thanks for the input guys.

Should I go with OEM Stihl bearings for this rebuild, or is there a comparable aftermarket bearing that is as good/better?

What is a good place to get replacement parts for this saw at? The only online place that i know of is Bailey's Online, is there a better place out there?

I want to get this thing completely tore apart this weekend, after all arbor day is Friday! What a great excuse to work on my chainsaw!

I should post a pic of the chain that I sharpened for my MS250, It cut like butter, but I am afraid that I may have taken off too much metal.

Thanks again for the imput!

-Jack

 

[jgrady1982]

So I made a bunch of progress on this rebuild today. I completely disassembled the saw yesterday and then cleaned it all up in the parts washer today. I made the case splitter from a piece of 1.5" angle iron that I cut to 6 inches long. I then drilled three 0.5" holes in the center of the iron using my dial calipers to "find" the two bar mounting studs and then the crankshaft. It worked great. I was a little off, maybe a 100 'thoul so I will probably open those holes up to about 50 thou over a half an inch, once I get a bigger drill bit. But with a little help of some fender washers I was able to "overcome" my measuring mistake and get the cases apart. The tool worked great, I am going to sand it and paint it tomorrow and keep that in my box for future use...hopefully!

I got all the parts cleaned up in my parts washer and then took all the plastic and also the bar holder and washed them in the dishwaser tonight. That thing did an amazing job at cleaning up all the plastic. Wow!

The culprit for this saw being on the fritz is a bad crank bearing that let loose on the flywheel side of the crankshaft. The bearing let out and then a small strip of metal on the flywheel side engine case was chipped off. Also it looks like the flywheel may have scrapped the coil, but the damage looks minimal at best. I broke the clutch shoe holder as well as the small key that locates the flywheel to the crankshaft when I was breaking this thing apart.

Also it appears as though the crankshaft scrapped the inside of the flywheel side case as evidenced by the large gouge on the counter weight on the side of the crankshaft.

There is no up and down play on the connecting rod, and the piston and cylinder look like the bearing went at the beginning of this saws life. There are not gouges or scratches on the cylinder and the piston has no carbon build up on the dome or anywhere else. Pretty clean top end.

I am going to order a new side case, woodruff key and crankshaft, as well as piston rings and a hone to hone up the cylinder. What do you all think about the piston? Clean it up and re-ring it, or get a new one?

Here are the pics:

Case splitter tool...

Flywheel side case

Messy bench!

Crank gouge

Clutch side case, all cleaned up

 

[jgrady1982]

Ready to go

From doing my homework on this rebuild here at arboristsite, I have realized that I am about the 1,000th person to rebuild an 028AV Wood Boss. So sorry about posting this here, I am sure that most of you saw "experts" probably get annoyed by "another 028 rebuild thread."

Thanks though for looking...and commenting!

-Jack

P.S. Good call on the bearing you guys! Spot on.

Does anybody know the best place for OEM Stihl crank bearings???

 

[roostersgt]

Stihl bearings only come from a dealer and they are not cheap. You might be better off buying a good used crankset w/ bearings from Chainsawr (site sponsor) or Ebay. Helpful hint when reassembling case. Use extra long bolts, the same thread as the ones you took out, to initially tighten the case, then remove them and replace with the originals. After the case is all tightened up, it will feel as if the crank assembly is "locked up". It is. Take a rubber mallet and smack both ends of the crankshaft hard. That should loosen it up.

 

[jgrady1982]

Stihl bearings only come from a dealer and they are not cheap. You might be better off buying a good used crankset w/ bearings from Chainsawr (site sponsor) or Ebay. Helpful hint when reassembling case. Use extra long bolts, the same thread as the ones you took out, to initially tighten the case, then remove them and replace with the originals. After the case is all tightened up, it will feel as if the crank assembly is "locked up". It is. Take a rubber mallet and smack both ends of the crankshaft hard. That should loosen it up.

Awesome! Thanks for the tip...please, keep them coming! This is my first rebuild!

I can take all the knowledge that I can get.

Thanks again,
Jack

 

[Bob95065]

I just rebuilt a 028 Super I got from a guy on craigslist for $20. The bottom end was in great shape. He tried to run it with a gas-ATF mix. It didn't work. The piston looked like it was straight gassed. I saved the cylinder using muriatic acid. It cleaned up really well.

I bought the replacement parts from Northwood Saw. They are a sponsor here and are listed above this thread. I bought a Metor piston, impuse and fule lines, carb kit and the gaskets I needed. The saw went together easily and started right up. This is only my third rebuild like this.

The saw didn't come with a b/c so I bought a Stihl 18" set from eBay. I want to keep this one so I went with the best.

I'm going up to my friend's house to cut up some pine tomorrow afternoon. I can't wait to see how it does. When I got it my plan was to rebuild it and sell it. When I took it apart I was impressed with the build quality. The design reminds me of my 066 that I took apart to repair. I tend to go with older machines because they are made better. I have read complaints about the weight of these saws but IMHO it is worth it to get a well made saw that will last a long time.

Bob

 

[roostersgt]

Bob,

Couldn't agree with you more. Great saw and built to last.

 

[Mastermind]

I figure that crank is fine.....check the big end bearing cage for wear or flaking. You can use an aftermarket bearing on the flywheel side....just be sure to use a high quality bearing, like Nachi. The PTO side is a Stihl only proprietary item. I would use a OEM gasket and seal kit as well. The piston appears to have too much wear....I like Meteor myself.

Your looking at well over 100.00 in parts but the 028 is a well made saw that deserves to be fixed.

 

[jgrady1982]

I finally got the saw put back together tonight. I had to buy an ebay case and crankshaft, it must have been a newer 028 wood boss becuase there some suttle differences, but nothing to hold up the build any further.

I cleaned and installed a carb kit tonight, and have both the "L" and the "H" screws turned out 1 and 1/4 turn from all the way closed.

O yeah, I put in an HL Supply 028 super piston and cylinder, so this is a 46mm cylinder 2mm bigger than stock.

I went to start the saw tonight and no go, it just floods out and gas pours out of the exhaust. I thought this was becuase there was a small tab that was keeping the exhaust from seating all the way down to the cylinder, but I ground off the tab to get a nice 100% seat against the cylinder, but it still floods out when I crank it and it will not start.

Also the starter does not want to rewind all of the way back into the saw. What could be causing this?

I tested for spark with the ignition set to run and the spark plug in the boot, but not touching the cylinder, and there was spark.

Here are the pics:

Here is that tab that I ground off on the side of the muffler, just above the spark arrestor screw.

 

[kr5258]

...I went to start the saw tonight and no go, it just floods out and gas pours out of the exhaust.

Also the starter does not want to rewind all of the way back into the saw. What could be causing this?

You probably flubbed the carb rebuild. Look at the IPL for the correct gasket sequence.
The recoil is easy, pull it off the saw and grab the line above the rotor. Pull it out a little bit and then use the line to put another turn on the rotor in the same direction (against the spring) as pulling when starting.

 

[jgrady1982]

I did flub the carb rebuild. I re-used one of the old gaskets instead of installing the two new ones that came with my rebuild kit. Plus I also had the order reversed, so I switched that up and wallah..it fired right up.

But two new problems. The first one is that gosh-awful pull start rope. From starting it it now hangs out about 9 inches from the case, it is even more loose than before. I have the OEM service manual and read the section that talks about how to re-wind it, and I have no clue what they are talking about. I have no idea how to "re-tension" the re-wind spring.

Also here is the other issue. I had to get a new-er ebay 028 case halves for this re-build. Well these are newer than the old halves that they replaced and that plus the combination of the 028 super cylinder, now the exhaust will not seat correctly to the cylinder. It looks like Stihl switched exhaust manifolds on the 028 at some point and the new manifolds now bolted to the cylinder x2 and then to the case halves x2, as opposed to the old manifold that was just held in place with two screws to the cylinder and then two more screws hled the screen in place to the manifold, on the old models it looks like they never bolted to the case.

So, since I have newer case halves plus an 028 super cylinder I need a new exhaust manifold. Does anybody out there have one sitting around?

Thanks,
Jack

It runs nice, but I feel like I can hear an exhause leak, plus it is very loud.

Here are the pics:

How the F do I fix this?????

I replaced this guy with the two proper gaskets and then I reversed the order of the two gaskets on the other side.

You can see here the small welded nut hitting the case.

Super safe...I already soldered the bass end that goes into the start switch, but it broke off, I am going to order a new switch and then re-solder it on. I am probably going to use some new wire as well....enless somebody has a better idea.

 

[fearofpavement]

Don't run the saw until you get the correct exhaust on it. It could cause engine problems. Stihl did make changes to the 028 engines and exhaust systems during its production run. I have an 028 Wood Boss AV EQ listed in the classified here and it shows a photo of its exhaust. I also have an 028 Super Wood Boss AV (no photos) and the exhaust looks completely different. You likely need the Super type exhaust.

Don't get discouraged. Look how much you're learning. It'll eventually get straightened out. Glad you figured the carb. That is a very common error.