Since I got both my total 045/056 rebuilds from a couple years ago running after many false starts (or no starts at all), I've still never put either of them through the paces for very long. When I tried to do some milling with the 045 Super a few weeks ago, it wanted to only be started with the high jet screwed in, but had no power there, and then had to frantically turn it out a full turn as fast as I could to develop power. Screamed great at top end there, but didn't really want to idle there very well no matter what I did, and would die as soon as I touched the throttle off idle.. And as soon as it died, had to screw hi jet all the way back in to start it. Switched out the carbs (between the saws, I rebuilt three carbs and bought one rebuilt one) and the new one wants also to start with high jet screwed in, but runs way too rich if I try to back it out. Screwed in though, high runs great, idles good, no problems at all.
I remembered from all my study on every quirk of these saws that there were some carb models that wanted the jet screwed in because they had a bypass, but had never nailed down what I had out of the four carbs, how to tell which was which. Looked at some old threads, and I see the Tillotson 221A had a bypass and the 118A did not. I only just recently came to understand welch plugs and how they can be the problem, and never changed the welch plugs on any of my rebuilt carbs before because I didn't know how to remove them, so know that could also be my issue. For the moment I'm happy with how it's running and in no hurry to take the decently working carb off it to check if it has a bypass or not, but I'll get to it soon. Think they all may be 118A's actually, just varying states of bad welch plugs and maybe a clogged low side in the one I just took off. Cause seems like maybe the one I have on now was still running a little rich screwed all the way in, compared to how it was really screaming with the other carb opened up a full turn. Hopefully I held on to some of the new welch plugs I never installed, though, now I know how to check if they're leaking and replace them. Think that may be where a lot of people get tripped up who don't know carbs well, is not taking the time to check if welch plugs are leaking and/or not know how to replace them. Pretty simple now I know, but the only non-obvious thing in a carb rebuilding process.
The frustrating thing on so many old threads of carb problems - and this seems to be true of any mechanical issue on any forum that is hard to diagnose - is the OP never says in the end if he fixed the problem and how. There's pages of discussion of "tried this tried this tried that" and then it just ends. Probably half the time the OP just gives up and goes out and buys a new chainsaw or whatever.
I remembered from all my study on every quirk of these saws that there were some carb models that wanted the jet screwed in because they had a bypass, but had never nailed down what I had out of the four carbs, how to tell which was which. Looked at some old threads, and I see the Tillotson 221A had a bypass and the 118A did not. I only just recently came to understand welch plugs and how they can be the problem, and never changed the welch plugs on any of my rebuilt carbs before because I didn't know how to remove them, so know that could also be my issue. For the moment I'm happy with how it's running and in no hurry to take the decently working carb off it to check if it has a bypass or not, but I'll get to it soon. Think they all may be 118A's actually, just varying states of bad welch plugs and maybe a clogged low side in the one I just took off. Cause seems like maybe the one I have on now was still running a little rich screwed all the way in, compared to how it was really screaming with the other carb opened up a full turn. Hopefully I held on to some of the new welch plugs I never installed, though, now I know how to check if they're leaking and replace them. Think that may be where a lot of people get tripped up who don't know carbs well, is not taking the time to check if welch plugs are leaking and/or not know how to replace them. Pretty simple now I know, but the only non-obvious thing in a carb rebuilding process.
The frustrating thing on so many old threads of carb problems - and this seems to be true of any mechanical issue on any forum that is hard to diagnose - is the OP never says in the end if he fixed the problem and how. There's pages of discussion of "tried this tried this tried that" and then it just ends. Probably half the time the OP just gives up and goes out and buys a new chainsaw or whatever.