Let's play diagnose the farm boss chainsaw.

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So, either I have a bad engine or something is wrong that I already "eliminated". I've got $12,000 worth of labor in this saw so need to get it figured out. lol.
Unless somebody can think of something that would cause this bogging, poor tune, lack of power thing that I missed... I think I've hoed up all the ground...
 
So, either I have a bad engine or something is wrong that I already "eliminated". I've got $12,000 worth of labor in this saw so need to get it figured out. lol.
Unless somebody can think of something that would cause this bogging, poor tune, lack of power thing that I missed... I think I've hoed up all the ground...
What is the history of the saw how did it develop?
 
It's a clam shell. Clams bite hard and hold on. Please do not send this saw to me under any circumstances. I already have four clam shells on board. All of them now run OK, but only after much TLC by their owner--me. Working on these saws and trying to fix them is a massive test of your patience and a first class PITA.
 
Ok, back from the airport. That was a mess. Part of Atlanta was blocked off by protesters so I took an alternate route and did fine until the airport which was jammed up. Got er done.
Did someone figure out the saw while I was gone?
 
I just had an epiphany! I have been wracking my brain (what little there is of it) regarding what this issue could be and I am just now recalling a Stihl 029 Super I had a similar issue with a couple years ago. In that case, it turns out the piston skirt was broken which changed the porting. I'm wondering if this is something similar. Anyway, that's where I'm going next. Into the engine. It's the only place that hasn't been visited... I'll post my findings.
 
I just had an epiphany! I have been wracking my brain (what little there is of it) regarding what this issue could be and I am just now recalling a Stihl 029 Super I had a similar issue with a couple years ago. In that case, it turns out the piston skirt was broken which changed the porting. I'm wondering if this is something similar. Anyway, that's where I'm going next. Into the engine. It's the only place that hasn't been visited... I'll post my findings.
Been there and done that when I upgraded a 310 to a 390. The crank bearings were shot and three of the steel balls were missing from the races. Lord knows where they went or how they broke loose. Both seals were also shot. Right front bar stud was frozen. I gave up trying to remove it. Flywheel has to be removed.

You will have every piece of this saw lying on the bench before you are through. It's a nice rainy day excursion. Good luck!
 
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I just had an epiphany! I have been wracking my brain (what little there is of it) regarding what this issue could be and I am just now recalling a Stihl 029 Super I had a similar issue with a couple years ago. In that case, it turns out the piston skirt was broken which changed the porting. I'm wondering if this is something similar. Anyway, that's where I'm going next. Into the engine. It's the only place that hasn't been visited... I'll post my findings.

Wow. Excellent thought. I would probably have never come up with that one. Good luck with it!
 
Heading out to the shop now to investigate the issue...
Inquiring minds want to know...

Other than the carb taking adjustments, I've got a 290 that shares a lot of the symptoms.

I'm going to throw a set of Cabers at it and check the other checkable possibilities as well.
 
Problem solved. I have finally discovered the issue. I'm fairly thoroughly angry at myself for my poor memory. The piston had a piece of skirt missing from the intake side (pics later). I'm mad at myself for two reasons:
1. I have encountered this previously and went through a long diagnosis process for that. It was an 029 Super.
2. If I had been more diligent in my cylinder inspection, I could have seen this issue as it would have been visible through the intake port. And I had multiple opportunities to view it during all the carb changes. Duh!
Rather than just change the piston, I put in a new Huztl kit (after spending some time on it with the grinder;))
I haven't put it in wood yet but do have the saw ready to go with bar and chain. I can't believe how many hours I've invested into this critter. Maybe gonna put it in my line up for a while and extract my vengeance from it.
Anyway, this long saga is coming to a close. Thanks again for the ideas and support.
 
Problem solved. I have finally discovered the issue. I'm fairly thoroughly angry at myself for my poor memory. The piston had a piece of skirt missing from the intake side (pics later). I'm mad at myself for two reasons:
1. I have encountered this previously and went through a long diagnosis process for that. It was an 029 Super.
2. If I had been more diligent in my cylinder inspection, I could have seen this issue as it would have been visible through the intake port. And I had multiple opportunities to view it during all the carb changes. Duh!
Rather than just change the piston, I put in a new Huztl kit (after spending some time on it with the grinder;))
I haven't put it in wood yet but do have the saw ready to go with bar and chain. I can't believe how many hours I've invested into this critter. Maybe gonna put it in my line up for a while and extract my vengeance from it.
Anyway, this long saga is coming to a close. Thanks again for the ideas and support.
Good work persistence pays now you can sleep , maybe!
 

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