Stihl 028 av super carb question

[WNCburner]

Hello- New to the site, but have learned plenty already. I just picked up an 028 super. I cleaned the air filter, adjusted the chain tension, filled 'er up with fresh mix and bar oil then started the saw. Everything seems to work as it should: idle adjusted properly, bar and chain are getting oil, revs up well, etc. I cut a few cookies to get everything warmed up and then figured I would check the carb adjustment screws. The low was set at 1 1/4 turns out, but the high was 1/2 to 3/4 turns out. I set it at 1 1/4 turns out, and the saw won't rev up for me. I'm scared to run it set too lean. I'm thinking that a carb kit might be the way to go, but I don't have a lot of experience with these two stroke engines and thought I would ask y'all to see if there is something else I should check out first. Thanks in advance.

 

[smokinj]

ok let me get this right it was running good before the adjustments

 

[WNCburner]

Yes, it was running fine before I backed out the high adjustment, and runs fine if I lean it out like it was when I got it. Just don't want to burn it by running too lean.

 

[smokinj]

Yes, it was running fine before I backed out the high adjustment, and runs fine if I lean it out like it was when I got it. Just don't want to burn it by running too lean.

heres the best info http://web.archive.org/web/20051018212959/www.madsens1.com/sawtune.htm

 

[HittinSteel]

Have you pulled the muffler and had a look at the piston? If it looks fine, I'd keep running the saw where it wants to be run. Make sure the saw is 4 stroking at wide open throttle or get a tachometer and check your wide open RPM's against the suggestions from the manufacturer. If the piston looks bad, let us know.

 

[WNCburner]

smokinjay- the link talks about an upcoming race...I couldn't find any info related to my question, maybe I'm missing something?

HittingSteel- Yes, the piston has some light scoring. Looks like I have some work to do here. What do you recommend?

 

[smokinj]

smokinjay- the link talks about an upcoming race...I couldn't find any info related to my question, maybe I'm missing something?

HittingSteel- Yes, the piston has some light scoring. Looks like I have some work to do here. What do you recommend?

http://web.archive.org/web/20051018212959/www.madsens1.com/sawtune.htm

can you post a pic of the scoring?

 

[HittinSteel]

Some others can chime in, but I'm wondering if the saw has an air leak at the crank seals. If you don't have the equipment to test it for a leak, it may be worthwhile to take it to a dealer and have them test it. Shouldn't cost much as it just involves blocking the intake and exhaust.

 

[WNCburner]

smokinjay- that's an awesome link, the .wav files are a nice touch.

HittingSteel- here's an out of focus pic. I have a local small engine shop, as well as a stihl dealer about an hour from here. Perhaps I'll drop by and see what they think.

 

[smokinj]

smokinjay- that's an awesome link, the .wav files are a nice touch.

HittingSteel- here's an out of focus pic. I have a local small engine shop, as well as a stihl dealer about an hour from here. Perhaps I'll drop by and see what they think.

yep thats a bad pic! and the best way to tune is by ear

 

[HittinSteel]

I'd drop it by the dealer and see what they think. Maybe they will give you a diagnostic opinion and then you can take it from there. Would hate to see you chase a carb problem with a rebuild unless you know it is the carb for sure. I rebuilt a carb recently only to find it was a problem beyond the rebuild....... on the other hand a carb rebuild is generally very inexpensive and a good thing to know how to do. If it doesn't work, you could chalk it up to experience as I did.

 

[WNCburner]

Thanks for the help, fellas. Do you think it is safe to do some cutting with the carb adjustments set where the saw wants to run well, tuned by ear? Should I hold off until the dealer can check it out?

 

[smokinj]

Thanks for the help, fellas. Do you think it is safe to do some cutting with the carb adjustments set where the saw wants to run well, tuned by ear? Should I hold off until the dealer can check it out?

are the limit caps still on there

 

[WNCburner]

no limit caps.

 

[smokinj]

no limit caps.

if it where my saw the scoring seem to be light I would tune it by ear and make sure your getting it to 4 stroke at wot and no load and run it.as old as that saw is and it does appear to be very light scoring I'd tune it and run it...imo

 

[HittinSteel]

I agree, no telling when that scoring occurred and could have been do to a bad mix at some time. Just make sure you have a good mix and run it until you can get to the dealer. Just make sure it's 4 stroking at WOT.

 

[WNCburner]

Thanks again! I like this heavy old saw, and hope that it will be a good tool for helping me pile up some splits for next season and beyond. I'll keep the mix fresh and the filters clean and hope for the best.

 

[smokinj]

worst case is a rebuild and at the age that it is just run it you have to.

 

['bert]

Digg'en up the oldies here a bit, does the WOT adjustment wav file work for other people? I get a page saying it can't be found. If someone has this file saved could you please PM me as I would like to here it. Thanks.

 

[WNCburner]

Hey, 'berta--

Try this link. If it doesn't work, let me know and i will save it and send it to you. By the way, it took a couple of minutes to load even with a fast connection. (broken link removed to http://www.madsens1.com/MNUsawmaint.htm) click on saw tuning, and use the links in the article. Hope this helps.

 

['bert]

Thanks that one worked, I was also able to find it (copies of this complete article) on a few other websites last night.

 

[WNCburner]

Diggin' into the archives a bit here, but wanted to post an update in case someone reaches this thread in the future during a search. The 028 and some other saws of this vintage have the choke flap built into the air filter. The spring used to disengage the choke when lever is set in RUN position had weakened. I took a few links out of the spring, retuned the carb as per the madsens site, and the old girl rips! A very late thanks to HittinSteel and smokinjay, I appreciate your input.

 

[oldspark]

Thanks again! I like this heavy old saw, and hope that it will be a good tool for helping me pile up some splits for next season and beyond. I'll keep the mix fresh and the filters clean and hope for the best.

I know its all relative but I bought a 028 super about a year ago and it is a light saw compared to my 045, I do like the power to weight ratio, I am sure the new stuff is a lot better but for now my old stuff serves me well.