Originally Posted by rvbuilder2002
If the torsion spring and Spring Retainer are properly installed, and there is no abnormal friction in the throttle cables, we have found that the system performs very well and the carb synch is very accurate through the entire throttle range (as checked on multiple ULS RV-12's).
I don't want to start a battle with the expert, just sharing my experience.
My carbs would not stay in balance, the problem was tracked to the cables were not moving evenly, measured with calipers. I discussed this with McFarlane and they offered to check my cable for problems. I thought maybe there was problem where the cables came to the "Y" into one cable.
I pioneered the idea of adding a 3# additional expansion spring and it solved my balance issue as far as the cables traveling equally.
I was felt I was using a bandaid to hide a cable problem so I bought a new throttle cable, installed it with the upmost care and large radiuses. Then I removed the additional springs. the travel on the cables would occasionally be different, I could lightly pull on the short cable and it would move another .040 out. Maybe engine vibration of unbalanced carbs will nurse the cables into position with just the tension of the torsion spring, but I felt they should move equal without vibration help.
I put the #3 spring back on with the torsion and have not looked back. This was well over 100 hours ago.