Saws Losing Power When Turned Sideways

[Vernon Tull]

OK -- Here's the next question. Both my newer MS290 and old reliable 028 saws lose a good deal of cutting power and engine speed when turned sideways to cut a tree. When they are held straight up and down as to cut firewood logs they run great with all the expected power. I use only non-ethanol gas with the recommended Stihl 50:1 mix.

What say ye?

 

[SilverKing]

seems like all saws are slower in felling cuts.If its bogging out might be carb issues.

 

[oldmar]

I have been told that a saw that loses power when rolled is suffering from mix pooling in the crankcase, and enriching when that mix runs into the transfers. I am not entirely certain that I believe this.

I have also been told that it can indicate leaking crank seals- when the air leak is covered with mix, the saw runs rich and loses power. I think that this sort of ties in with the first theory, and again, not certain.

I have an 026 that behaved this way, and idled badly, due to a bad carb. Good carb straightened her right out.

 

[nmurph]

Does it do this with a full tank? I recently replaced the fuel line (OEM) on a 361. It did the same thing. What I finally figured out was the line was curling and not picking up fuel in a near-empty tank. I let it sit for a couple of days and the line went limp and hung as it should.

 

[oldmar]

I let it sit for a couple of days and the line went limp and hung as it should.

Aaaaaannnnddd Sigged.

 

[bplust]

In my experiences, 90% of the time that happens, there's an air leak, albeit minor, but must be fixed. The other 10% is a weak main diaphragm in the carb. Leak test that saw!