Here is a topic I think needs some discussion. I see a lot of throttle springs on engines in hot rods that are hooked up incorrectly. Most are done so the throttle shaft hole will wear out very quickly, ruining the carb. Many are like the 'Bad' drawing shown below. By hooking the throttle actuator in the top hole and the spring to the bottom hole on the throttle lever, there is a net force on the drilled hole in the carb base equal to twice the spring tension! Forces are shown as arrows on the drawings. Next up the food chain is my 'Poor' method which is slightly better by hooking the spring to the same hole as the throttle actuator but since they are not directly in line as in the 'Better' drawing, the forces partly cancel each other but there is still a downward force on the shaft that will prematurly wear out the hole. The 'Better' drawing would be a good situation if the spring and shaft could be kept in constant alignment but as the throttle is opend and closed, they assume different angles and there is wear. The 'Best' case as shown is how yours should be hooked up. The throttle actuator and spring are both hooked to a separate bellcrank that has ball bearings or nylon bushings that can stand any force that the spring can impose on it. Then there is a separate rod that goes from the bellcrank to the carb lever thus there is virtually no extra forces on the throttle shaft hole. Remember these throttle shafts usually go through soft aluminum or pot metal and are not lubricated.
[ November 14, 2002: Message edited by: email@example.com ]</p>