I have a Honda Countax 13hp V twin gxv530, electric start with no pull start fitted, it is in regular use but has started to surge or hunt throughout the throttle range, it has new filters, new throtle cable ( old one was sticking) new plugs, fuel is new, the engine has always started well and given no previous problems and therefore not needed any changes to any adjustments, now getting perplexed any help will be much appreciated.