hi bruce upon reading information you sent and further investigation of the choke butterfly in the start position i found by loosening the choke butterfly on the shaft then closing the choke to the on position i could then tighten the scews up tight with the butterfly more central in the carby ventury,the butterfly was fouling on the carby body,the choke is closing fully now and starting appears to require less pulling on the starter cord, laugh thanks again graham cheers