I’ve noticed that the X30 Tillotson carburetor requires adjustment of both the L and H screws even when conditions are seemingly identical on consecutive days. The idle may disappear, and I have to adjust the L screw slightly all the time. At high RPMs, the EGT can be 50°C lower than the previous day with the same settings, requiring the mixture to be leaned out. Is this normal, or could there be something wrong with the carburetor? I’ve already changed gasket set and checked that the needle holds pressure as it should.
I never touched the low speed setting on my KA or x30 Set and forget for the most part.
Do you have a weather station? I think you’d be surprised at just how much of a difference the morning versus afternoon and even day to day can change.
I have an app on my phone to check data and this site is also nice.
We set the L and keep it there 95% of the time, the H is the only one being adjusted.
We use an APP for the base setting and from there, generally the X30 carb is very easy to work with, but some things Can screw it up.
1 Bad gasket set, check that nothing is damaged, If In doubt change them.
2 Worn throtle Axel, had one where the arm and the axle had 20degress play,
3 Empty them for fuel every time after use, i just use the pump for checking popoff pressure.
4 Check popoff pressure, check thats its not leaking and are Holding pressure.
5 Check that L screw is towards the reeds and H screw towards the intake there is a difference between them.
Thanks for the replies! I think I’ve got it sorted out. Turns out the needle screws were loose and turning on their own while driving. Now that they stay put, the mixtures have stayed right without needing constant tweaking.