044 Top Ring Got Hot, Lean?

[Scottnc]

Pulled the muffler and sparkplug to do an inspection of my 044 after cutting a bunch of red oak firewood rounds. The log measures 41", using a 24" bar. This was the first hard work this saw has done since it was ported and compression increased. And it was worked hard. The cylinder and piston look fine, the plug dry and light brown, but the top ring has darkened. It is free in the groove with no scoring in its face. I checked that the carb was fat enough to four stroke before starting to cut. Half way through the job I got nervous when the saw was not four stroking when unloaded in the wood, so I stopped and backed the hi-speed out another eighth turn. That did the trick, now the saw would four stroke wide open while in the wood under a slight to no load.

Think I ran it to lean enough at the beginning to cook the top ring?

 

[cookies]

I think the H needle was originally set with the saw not fully heated up so it was adjusted right to the edge but still safe. I also now think you have it set a hair rich, once it touches wood it should not 4 stroke. A temperature change can cause the h side to need adjusting. I typically crank and idle the saw then rev out the excess accumulated oil from storage then start a cut listening to the engine work. After a couple smaller cuts I listen for the 4 stroking at max rpm, remember once heat soaked it will 4 stroke less noticeably or even not at all. This is why most manufacturers have moved to setting by tach. I seem to favor (by engine sound) 2-300 rpm under stock recommended numbers if everything internal is oem.

 

[Scottnc]

I think the H needle was originally set with the saw not fully heated up so it was adjusted right to the edge but still safe. I also now think you have it set a hair rich, once it touches wood it should not 4 stroke. A temperature change can cause the h side to need adjusting. I typically crank and idle the saw then rev out the excess accumulated oil from storage then start a cut listening to the engine work. After a couple smaller cuts I listen for the 4 stroking at max rpm, remember once heat soaked it will 4 stroke less noticeably or even not at all. This is why most manufacturers have moved to setting by tach. I seem to favor (by engine sound) 2-300 rpm under stock recommended numbers if everything internal is oem.

Cookies - It sounds like we are on the same page regarding the high side setting. I warmed the saw then checked that it'd four-stroke and went to work but I did not clear out the crankcase as you recommend. Cutting this oak log no doubt pushed the limit for heat buildup due to the duration of cut and the saw being asked for max power the entire time. From time to time I did free-rev it out to verify it would four-stroke out of the wood. It's bad on me I did not have a screwdriver with me, early on I was concerned the saw was a bit too lean - but I kept cutting. Currently it may be a touch rich but it is reassuring to hear just a bit of four-stroke as the saw hits max rev's just as the chain is coming out of the cut.

Guess I'm lucky the damage was limited to a top ring. It's time to order a set of Caber's. And, add a screwdriver to my wood cutting essentials milk crate.