Stihl 028 super rebuild went bad

Arborist Forum

Help Support Arborist Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.
They normally do have lots of power when they run lean up top as long as they don't lean out such as from a seal or boot leak where the leak gets worse with speed/load. Idle is affected by the idle circuit...so you had a good idle tune and probably no leaks...but the high side was a bit lean

Sent from my LM-G820 using Tapatalk
Was runnin like never before real crisp!
 
Trying to build an engine off the internet with 20 different advisers sometimes works............sometimes doesn't.
Trying to build with aftermarket, inexpensive parts sometimes works...............sometimes doesn't.
Trying to gain knowledge enough for a complicated task, without prior experience sometimes works.......well you know
 
Trying to build an engine off the internet with 20 different advisers sometimes works............sometimes doesn't.
Trying to build with aftermarket, inexpensive parts sometimes works...............sometimes doesn't.
Trying to gain knowledge enough for a complicated task, without prior experience sometimes works.......well you know
I get your drift. That being said, i have learned a lot.
 
Spec was 1.25, the hi side was about an 1/8 less.
Personally i don't go by spec turns out or in except as a base setting to get it running...then i set my idle speed, turn base idle in until the saw takes off some...add L screw until it slows...fine tune it so it doesn't load up at idle. Then wind it up for the high speed...i go rich...smoke and low revs...then turn it in until it hits peak..then back out til it burbles.

Then back to idle...rip it full throttle...if it drops revs on tip in, give it a bit more idle fuel...if it sputters rich on tip in..take some idle fuel away. Once it accelerates clean off idle...set base idle where you like it. Punch it wide open again...should accelerate smoothly up to the 4 stroking high setting...then finish off the high speed tune in wood. Sounds complicated...takes about a minute.

Sent from my LM-G820 using Tapatalk
 
Personally i don't go by spec turns out or in except as a base setting to get it running...then i set my idle speed, turn base idle in until the saw takes off some...add L screw until it slows...fine tune it so it doesn't load up at idle. Then wind it up for the high speed...i go rich...smoke and low revs...then turn it in until it hits peak..then back out til it burbles.

Then back to idle...rip it full throttle...if it drops revs on tip in, give it a bit more idle fuel...if it sputters rich on tip in..take some idle fuel away. Once it accelerates clean off idle...set base idle where you like it. Punch it wide open again...should accelerate smoothly up to the 4 stroking high setting...then finish off the high speed tune in wood. Sounds complicated...takes about a minute.

Sent from my LM-G820 using Tapatalk
Im screen capturing this, itll go in my chainsaw file
 
What does the plug look like ??? It may give you a clue as to what was going on inside the engine. I remember this rebuild and I would say you covered all the bases but things happen . Kind of a crap shoot sometimes rebuilding these old saws . It is defiantly lean seized .

Just one question . When your out cutting wood do you run the saw completely out of fuel at WOT before refilling the tank. This can cause a lean running condition.
 
What does the plug look like ??? It may give you a clue as to what was going on inside the engine. I remember this rebuild and I would say you covered all the bases but things happen . Kind of a crap shoot sometimes rebuilding these old saws . It is defiantly lean seized .

Just one question . When your out cutting wood do you run the saw completely out of fuel at WOT before refilling the tank. This can cause a lean running condition.
I have occaisionaly. Not a lot because its usually harder to start.
 
I did get the pump on the saw and somethings leaking. Now i gotta take it apart to get to the seals and see. Fathers day kinda got me behind schedule. I did get a nice p365 sig sauer this weekend though.
 
Sounds like just another case of damage from running a saw that was set too lean on the high speed mix. You really have to learn to tune the saw so that it has the 4-stroke burble at full throttle out of the wood and just barely cleans out as you start the cut. Unreliable things to go by are the number of turns out on the mixture screws, how much power you think it is making, setting the high rpm to some number with a tach, how well it starts and idles.
Set the H screw so rich that it burbles and runs slow and rough in the cut, stop the saw and turn the screw in a bit and make another cut, keep doing this until you reach the point where the engine just cleans out and runs nice and crisp in the cut. Stop there, should only take 4 o5 cuts to reach the sweet spot.
 
Back
Top