Came across this saw a couple months ago. While running at the sellers house it had an intermittent fast idle issue. Kinda depended on how you held the saw. Got home and found the throttle return spring broken And while poking at that I noticed the whole shaft was loose in the carb body. I figured it was bushing issue and I was able to find a place states side that deals Tillotson oem parts, so I ordered bushings and shaft and spring. When I got the new parts I discovered on tear down that it was the shaft that was the issue. Old and new above. So rebuilt and found two issues. 1) the throttle shudder had been worn because the shaft was katywampus and 2) now the machine ran at screaming idle. I figure it was the shudder. I had bought a 13$ chinese carb and when I threw that in, it calmed down. So I still had an issue in the Tillotson carb. I went back to Tillotson and got a new shudder and a rebuild kit and put them in this afternoon. What I found though was the shudder still didn’t want hit idle position. I grabbed a carb on the bench that goes on a Stihl MS280c and found the spring on that one was wound tight tight. So I wound the spring one more turn between stops. That pushed the shudder a lot closer to idle. Swapped the newly rebuilt Tillotson for the Chinese. Saw started well but idled fast. Backed the idle off 100% and it still ran fast. Then I checked the jets and found the low at about 1/2 turn out. I brought that to the normal 1 1/4 and that did the trick. Have only run it behind the garage, so no final judgement until I can make some cuts. And I can say, the OEM parts for the carb are not expensive. The shaft was like 5.50$. Everything else was under a buck, except the rebuild kit, which was still under 10$. It’s somewhere In Ohio, VE Peterson’s, so some of you my save on freight as well.
I got a 266se at the shop that I would like to get tuned up good. Worked on it some last winter & found out it needs a impulse bellows, ( Not sure that’s the proper term for it). Little rubber doughnut like thingy that sits under carb. Any ideas where to find one.
Under the carb...... I think that’s a vibration dampener. Also helps keep crud out of the metering valve side of the carb. Not sure which of those purposes would be more correct. Most carbs have that hole off to the side of that cover. The carb on mine is an HS 224a and the port to allow atmosphere pressure in is right in the center of that cover, which would sit right over the center of that donut hole. I’ve only seen that donut on the 266SE and on an older 61. I think you could get by without it. Not sure where to find one. Try one of the forums or a parts .com. And let me know how you make out.
The impulse for that saw is a direct port through the phenolic block to the carb. The gasket has hole between the two to accommodate that. It’s not like a others that run a separate hose to a division wall or like a Stihl that has a nipple from the cylinder for the hose to hit the division wall. First and third pics above show the impulse
