So, I got these two old saws I picked up, and MS250 and an 023. Both of them had crap original carburetors that didn't run well even with fresh oem walbro kits in them. I slapped 2 new china carbs on them and they ran better but not perfect still. I went and got a brand new Walbro WT 215 from local dealer and slapped that on, definitely made a small improvement on both, but still not perfect.
As far as I know, a saw shouldn't significantly change idle speed when you tip it sideways, like a couple hundred rpms seems acceptable, more than that, probably a carb or air leak issue seemed to always be the consensus.
It seems I've also learned that some saws have their fuel pickup in one spot or another, and if you say have the pickup sitting against the right rear of the tank and tip it counter-clockwise, it might speed up because it's not sitting in the fuel. This is kind of unavoidable as far as I know. Generally though I will position the pickup there at the bottom right rear of the tank as normally I flip the saw clockwise for a side cut more often, but I do both when limbing generally. Anyway I filled the tank of each full to avoid that being a possibility.
What surprised me is that the brand new MS250 actually ran worse than the old one I've been working on and scratching my head, and it seemed to behave pretty much exactly the same way, only worse. I realized this as I went to use it today for the first time, also bought it today. Filled it up, used the stihl mix oil btw, and let it idle for a good 10-15 minutes. Figured limbing a medium pine tree should be a good first run for a very light workout. No bucking, just limbing small limbs off. Cut really good, love the power of these, but I noticed as my joy faded that at least 2 times as I was going along when I tipped it sideways for a cut it would almost stall. I was really surprised as I thought it was gonna run perfect. Thought it was a fluke maybe the first time and kept going but it did it again, I recall at least 2x. Then I was like wtf? Sat it on the trunk and let it run upright for a bit and would tip it periodically. It didn't do it every time but once in a while it would really drop off, this was tipping it clockwise btw, like you normally would for a felling cut. I didn't like that one bit. It was idling really high already at around 3400 to 3600 so for it to drop down to 2k or less and almost stall that just seems unacceptable. (I had a Stihl rpm meter handy, always in my pocket). Manual says it's supposed to idle at 2800. I don't think dealer touched it and there is no L screw on the Zama carb. Kinda irrelevant anyway though because point is the older one I have does it too, but not as bad. I was chasing air leaks on the old one and spent a LOT of time on it, even yamabonded the damn boot to the cylinder, brand new walbro carb, and did a pressure test, which it passed. But after experiencing the exact same thing with a brand new one, and the 023 that is a similar design does it too, I'm really wondering wth is going on here. Is that just how they run?!? Its seems like they must be designed this way somehow or another, possibly in how the cylinder is designed, I don't know but its definitely one of the weirdest thing I've encountered on chainsaws yet.
As far as I know, a saw shouldn't significantly change idle speed when you tip it sideways, like a couple hundred rpms seems acceptable, more than that, probably a carb or air leak issue seemed to always be the consensus.
It seems I've also learned that some saws have their fuel pickup in one spot or another, and if you say have the pickup sitting against the right rear of the tank and tip it counter-clockwise, it might speed up because it's not sitting in the fuel. This is kind of unavoidable as far as I know. Generally though I will position the pickup there at the bottom right rear of the tank as normally I flip the saw clockwise for a side cut more often, but I do both when limbing generally. Anyway I filled the tank of each full to avoid that being a possibility.
What surprised me is that the brand new MS250 actually ran worse than the old one I've been working on and scratching my head, and it seemed to behave pretty much exactly the same way, only worse. I realized this as I went to use it today for the first time, also bought it today. Filled it up, used the stihl mix oil btw, and let it idle for a good 10-15 minutes. Figured limbing a medium pine tree should be a good first run for a very light workout. No bucking, just limbing small limbs off. Cut really good, love the power of these, but I noticed as my joy faded that at least 2 times as I was going along when I tipped it sideways for a cut it would almost stall. I was really surprised as I thought it was gonna run perfect. Thought it was a fluke maybe the first time and kept going but it did it again, I recall at least 2x. Then I was like wtf? Sat it on the trunk and let it run upright for a bit and would tip it periodically. It didn't do it every time but once in a while it would really drop off, this was tipping it clockwise btw, like you normally would for a felling cut. I didn't like that one bit. It was idling really high already at around 3400 to 3600 so for it to drop down to 2k or less and almost stall that just seems unacceptable. (I had a Stihl rpm meter handy, always in my pocket). Manual says it's supposed to idle at 2800. I don't think dealer touched it and there is no L screw on the Zama carb. Kinda irrelevant anyway though because point is the older one I have does it too, but not as bad. I was chasing air leaks on the old one and spent a LOT of time on it, even yamabonded the damn boot to the cylinder, brand new walbro carb, and did a pressure test, which it passed. But after experiencing the exact same thing with a brand new one, and the 023 that is a similar design does it too, I'm really wondering wth is going on here. Is that just how they run?!? Its seems like they must be designed this way somehow or another, possibly in how the cylinder is designed, I don't know but its definitely one of the weirdest thing I've encountered on chainsaws yet.
