Stihl 028 WB wont start after overworking the saw

[SEAM]

EIN = Intake
AUS = Exhaust
Make the arrow point the right way...

Looking at the first pics of the installed piston with the stuck rings the locating pins were on the exhaust side as well.

 

[lwn9186]

Ignore the arrow and put the locating pins to the intake side. Turn the piston 180!

 

[lone wolf]

Ignore the arrow and put the locating pins to the intake side. Turn the piston 180!

yup

 

[SEAM]

There are exceptions to the rule... some pistons need to be installed with the pins pointing to the exhaust. As long as the gap offset is wide enough, I would follow the arrow and other markings. Doesn't sound like anyone has been fiddling with the saw internals before.

 

[lone wolf]

There are exceptions to the rule... some pistons need to be installed with the pins pointing to the exhaust. As long as the gap offset is wide enough, I would follow the arrow and other markings. Doesn't sound like anyone has been fiddling with the saw internals before.

I am sure someone will be along soon that knows that particular model and will answer.

 

[drf255]

If its correct, more proof that flipping the piston is OK. Finger ports baby!

 

[lwn9186]

I don't recall Stihl using those circlips.

 

[JoPy]

Wow, good eye lwm. Like Seam said the arrow does point to exhaust... Should I still spin it?

The rings were just cleaned but Ill look into getting a set and Ill check out the clearance without a gasket.

As long as I have had the saw I have used Husqvarna XP oil at 40:1. Like Westcoaster said I'm sure grandpa was running all kinds of stuff through it over the decades, but he was the kind of guy who really takes care of things so I'm sure it wasnt any intentional abuse.

Thanks alot guys I really appreciate all the advice.

 

[Big_Wood]

the 028's had ring locating pins on the exhaust side. it's normal so leave it. there are alot of people here on AS that shouldn't be giving advice yet they do all the time anyways. all this talk about i'd replace that or replace this. heck it's an 028. fix'er up and run it. after that clean up she'll be good to go for another 20 years

 

[redfin]

What's the nub on the intake for if it doesn't capture a pin?

 

[drf255]

the 028's had ring locating pins on the exhaust side. it's normal so leave it. there are alot of people here on AS that shouldn't be giving advice yet they do all the time anyways. all this talk about i'd replace that or replace this. heck it's an 028. fix'er up and run it. after that clean up she'll be good to go for another 20 years

Do all 028's have the pins on the exhaust side, or just the 42mm

 

[Diesel Freak]

t: 5386978, member: ]... there are alot of people here on AS that shouldn't be giving advice yet they do all the time anyways. all this talk about i'd replace that or replace this. heck it's an 028. fix'er up and run it. after that clean up she'll be good to go for another 20 years [/QUOTE]

I agree that it's easy to say "throw parts at it" when it is likely that it could just be thrown back together and ran. That being said, IMHO new rings just make sense. It was a ring sticking to begin with and as stated earlier that saw has been thoroughly used. I would think of rings as preventative maintenance since it's already apart. As for the recommendation of omitting the base gasket, I'm too new to comment on that. I know I've seen it talked about here a lot but if you're like me and just want to get it going again without having to worry about "did I measure the squish right" then I would just install a new gasket and run it. FWIW, I've been lurking AS for a long time but this is my first post.

 

[Wood Doctor]

Occasionally you can omit the base gasket, use gasket cement (Permatex) instead, and then the piston won't even turn over because there is insufficient clearance. That has happened to me twice on two different Stihl saws. On the other hand, it often works to use the gasket cement alone. It's a chance that you can take.

On the other hand, mounting the rings and piston pointing the wrong direction is something that I never intend to do. That seems to be a pointless experiment.

 

[mikerecike]

Nice clean up.What did you use to clean inside the cylinder? Chemical or mechanical removal of that carbon in the combustion chamber?

 

[JoPy]

I used acetone. I put an old spark plug, poured in a pool of acetone and used the blunt end of a carpenters pencil to scrape around. Took about 10 minutes.

 

[mikerecike]

Thanks Jopy will try that

 

[JoPy]

Sorry its been a while to get back, been a busy summer for me.

So after the P&C cleanup I mounted the cylinder using Motoseal and left out the paper gasket. The clearance does seem to be fine so far since I haven't had it running yet...

I did a vacuum test by blocking exhaust and intake ports and pulled suction through the impulse line. It had a good seal. I rotated the crank and pressure raised and lowered accordingly then stabilized.

I vacuum tested the fuel line, its good. I vac tested the fuel tank and the cap does breathe.

I did a carb clean and reassembly and after some serious pulling had it running for 20 seconds (running very roughly) with the throttle wide open. (would stall unless WOT)
I haven't been able to get it running again since... I have a carb kit on order, well see what happens with a carb rebuild...

Anyone have any next step ideas?

Thanks,
Jon

 

[JoPy]

Forgot to mention that there is a spark. I shocked myself several times, just to be certain.

I was also curious about the exhaust assembly. Is the metal gasket at the cylinder supposed to be sealed with anything or is it a dry fit?

 

[redfin]

Your exhaust gasket is a dry fit.

 

[a. palmer jr.]

All the saws I've put together have the ring end gaps facing the intake..