PPS: Agreed that plastic bits don't appear to wear but plastic DOES has a tendency to creep with time and temperature and we have observed that a tiny change in poppette seat apature opening has a significant affect on idle speed . I think that the lifter (spider, given its shape, could be particularly prone to creep and this could be one of the causes of the idle issues a lot of people have experienced with this carby???
In my mind Victa intended that this carby should be a throwaway item when it plays up but its replacement cost was made prohibitively high.
I think you should patent the new cap screw adjuster design for idle adjustment - simply brilliant. But just a note for anyone trying to replicate what we've done, its important to start off with an engine that idles a bit too slowly - the idle screw adjuster is then screwed in to open the poppette a fraction to allow more fuel in at idle that increase the speed. Engine can be initially slowed down by adding 7 mm washers (1 - 3) between the carby body spigot and the bottom face of the cam boss. Ie. Adding washers will raise the cam up which reduces the poppette seat apature opening so idle speed reduces. Adjuster screw is then wound down to increase idle speed to what you want. ..... But I'm still a little uncertain as the what affect the springs have on this process and there are may possible spring combinations to chose from??
- BUMPS
