issue with 028 bogging down

[thompson1600]

I have a question on an 028 Super I'm rebuilding. The saw idles like a champ, but when you give it some gas it bogs, sounds almost like the chain brake is on. The chain brake is not on. The chain spins by hand when the saw is off, and I can get it to spin easily by adjusting the carb at idle. Just does not want to go good at accleration to high RPM's. I put my tachometer on it and could get it to around 11,000 with carb adjustments, but it was really bogging and did not sound good.

I used the recommended Stihl carb adjustment of one turn out for the H and L screws. Starts right up and idles great.

Has new crankcase gasket, oil seals, new fuel line, new tank vent, impulse line is good, been pressure/vacuum tested, carb just rebuilt.

Only thing left I can think of to try is new piston rings. Any other ideas?

Tom

 

[Damo]

So you're not a Stihl fan, by the look of it !! Can't help with your prob. as you've done most of the things I would suggest, but I'm just admiring your collection. What sort of trees do you cut in Minnesota, if you don't mind me asking?

 

[fishhuntcutwood]

So Tom to clarify, it's not under load when it bogs, you're just on the throttle, right? I know just enough to be able to tune a saw on my own, but didn't I read that a saw that can't reach peak rpm's is running with a rich condition?

There was a thread a while back where I think it was TonyM that explained the difference between hesitating and bogging, between lean and rich. You might do a search of his recent posts, and you'll find it. If not, do a search of my recent posts, and you'll see me asking him about it. It was probably a week ago.

Jeff

 

[Lobo]

Have you tried completely swapping out the carb. for another one and re-testing.

Something's been missed or not in view somewhere.

 

[HiOctane]

Don't laugh at his,but check the spring in the air filter that holds the choke flap,happens its too soft and when you accelerate the engine,the choke comes on partially due to softness of spring.To check ,run the saw w/o air filter,you gonna see if there is a difference.i bet 1.00 you just found the trouble.keep me informed.

 

[thompson1600]

1. What type of trees do I cut? Mainly I cut and mill trees for custom furniture. Up here it's usually Maple, Cherry or Walnut that I work with, but occassionally I get lucky and find an apple tree that's big enough to use. Otherwise I use the smaller stuff to turn on the lathe.

2. No, I have not tried completely switching out the carbs. The only other 028 carb I have needs a rebuild as it's not holding pressure.

3. Correct, it's not under load. This is just in running the saw. It starts and idles great. Set it down and let it run. But I can not get it to accelerate smoothly and up to high RPM.

4. I will check that spring, and switch out the air filter and try that. Interesting idea.

Thanks

Tom

 

[scotchguy]

Hi Tom ... off topic

Hi Tom,

I really like your furniture on your web site, I'm tempted, but I don't see any dimensions specified?

Also, I was really please to see that you have a pdf for the Stihl 064 on your web site as I have just acquired one from ebay (see my diagnosis thread). I just downloaded the manual but it would not open becuase the file was damaged. This happened twice and I would be very grateful if you would check the file and let me know if the problem is at your end or mine.

Many thanks, Ronald.

 

[Lawn Masters]

I think its at your end, cause I dowloaded the file awhile back for one I had here. If you'd like I can email you the PDF file.

 

[thompson1600]

Thanks on the furniture. I don't list dimensions, because most everything I build is a custom one of a kind piece. I started out a few years ago thinking about doing specific products (some seen on the website), but decided I didn't want to do production type building. I wanted to design and build pieces based on customer needs/wants and on pieces of wood I find to work with.

I checked the file and it appears to be OK on this end, but I'm not a computer guru so I may be wrong.

 

[BlueRidgeMark]

Tom, you do some beautiful work! Maybe someday I'll be able to afford you!

Meanwhile, I'll carefully delete my history file so my wife doesn't discover your site!

 

[scotchguy]

Thanks for the manual

Hi Tom,

Many thanks, I got the manual. It is a really nice pdf with all the hyperlinks ... not the scaned file I was expecting. Where the hell did you get it?

Thanks again! Ronald.

 

[Chris J.]

Perhaps the factory Stihl CD?

 

[Stihl Racer]

Back to the saw problem

Good start with the one and one on the H-L needles, but that only a reference. Depneding on where you are and age of saw etc. it will need finer tuning. get it started and just turn it about 1/8 turn and try revin up again, and keep going ig you notice it gettin better your on the right track. if it gets worse go the other way. get it to where you like the accel speed then tune the H. If you got no tach...pin it and lean it till you hear it high pitch and smooth then richen it a hair to compensate for when u get a load on it. Try that and let me know how it goes.

 

[thompson1600]

Well I got it running great now. I replaced the air filter because the air filter spring was weak. That helped, but I had to replace the rings in the end and now it's great.

Tom