Stihl 028 WB wont start after overworking the saw

[JoPy]

Hi fellas,

I have this old Wood Boss I inherited from my wifes grandfather. It used to be a stubborn starting saw, but I replaced the fuel filter, spark plug, and air filter a couple weeks ago and it has been kicking on second pull regularly. So this afternoon I was cutting up firewood and the blade was nice and sharp, spitting out chips like it should when I got to this really knotty crotch section and regretfully decided to go after it. The blade dulled up by halfway through and I kept going. The saw was running hot and I figured both it and I needed a break so I cooled it down for a few minutes and went back to it and the saw stalled.

It was running for about 5-10 seconds per start for a few starts. I figured I would try it again after a long cool down and now I cant get it to start at all... Where do I begin? Thanks for the help!


Rings

Top of Cylinder

 

[redoakman]

I would pull the cylinder of and have a look that brown film is badd.

 

[SEAM]

Looks like you got stuck rings, at least the lower one... There may have been carbon deposits in the combustion chamber that came loose and penetrated the ring grooves caused by the heat. The exhaust port still shows some chunks of carbon.

 

[Scott Kelly]

Looks like you need rings.. While you are apart with it might want to snag an 026 ignition coil if it has points.

 

[pioneerguy600]

First item of order, clean that saw up before pulling it apart, clean everything off around the cylinder and base, keep cleaning as each part is removed. It looks like the rings are stuck and causing low compression. Cylinder needs to be pulled off and inspected.

 

[JoPy]

You guys were right on about the sticking rings. Bottom one was getting stuck all along where the gunk is at and the top had a little bit of sticking going on in the same area. I gave everything a nice rub down and everything seems to be in good shape for being 30 years old. There are a few minor pits inside the cylinder, but no streaking at all. Its smooth as glass in there. Once the ring seats were cleaned up the sticking seemed to be eliminated as well.

Does anyone see anything of concern? Is there anything I should replace while its apart? I have to replace the gasket under the jug so it will be a while before any reassembly happens.

Thanks for the help!















After the cleanup...

 

[Fly By Night]

Have you considered leaving out your base gasket to increase compression?

 

[Scott Kelly]

I do believe they will clear without the base gasket, save you a little money on a new one. Plus extra compression never hurts! Use some yamabond or motoseal and throw her back together.

 

[lone wolf]

You guys were right on about the sticking rings. Bottom one was getting stuck all along where the gunk is at and the top had a little bit of sticking going on in the same area. I gave everything a nice rub down and everything seems to be in good shape for being 30 years old. There are a few minor pits inside the cylinder, but no streaking at all. Its smooth as glass in there. Once the ring seats were cleaned up the sticking seemed to be eliminated as well.

Does anyone see anything of concern? Is there anything I should replace while its apart? I have to replace the gasket under the jug so it will be a while before any reassembly happens.

Thanks for the help!















After the cleanup...

What oil are you using and at what ratio?

 

[Wood Doctor]

As lone wolf asked in #9, this fuel mix is an important issue. I am having a hard time believing that all that gunk and wear was caused by just one cutting session in which the saw got hot. This problem built up over time and finally a straw broke the camel's back.

 

[Deets066]

Nice job on the clean up, be sure and get that exhaust port cleaned up good too.

 

[lone wolf]

As lone wolf asked in #9, this fuel mix is an important issue. I am having a hard time believing that all that gunk and wear was caused by just one cutting session in which the saw got hot. This problem built up over time and finally a straw broke the camel's back.

Looks like petroleum base oil and not a good one at that.

 

[Rockjock]

Looks like petroleum base oil and not a good one at that.

Swampco??!!?? ( ok ok DieselShawn it was a joke!!! )

The clips look interesting omega shaped?

 

[Big_Wood]

What oil are you using and at what ratio?

it don't matter cause that saw has likely seen many many many different oils through it's lifetime. look at how dark the bore is. that's an extremely high hour saw! it's an 028 though so it's probably still got half it's life ahead of it LOL

 

[lwn9186]

Is the piston in backwards?

Looks like the pins are facing the exhaust side.

 

[drf255]

Turn the piston around.

Did you replace the rings or just clean them?

I'd put new caber rings in. While the old rings are off and you're flipping the piston around, bolt the jug on and check squish with no gasket. On my SUPER, it came in at .023 without a gasket YMMV.

All you need is a gas resistant sealer, like Dirko, yamabond, motoseal, etc. You don't need a gasket if the squish is OK.

 

[SEAM]

The arrow on the piston points the right way...

 

[albert]

The piston is on the right way. It is a 42mm. If I remember right, the arrow points to intake and the german word for intake is at the arrow.

 

[lone wolf]

The piston is on the right way. It is a 42mm. If I remember right, the arrow points to intake and the german word for intake is at the arrow.

Dont I see the ring end locating pins facing the exhaust? They should be facing the intake .

 

[drf255]

42mm 028's never made much sense to me. A beefy saw with such small displacement.

If it were me, I'd sell the original P&C and upgrade to a Super jug. I got an OEM super P&C on ebay for $50 and sold my 44mm for $50.