I have an RC Showcase 26cc with a rear Walbro carb. I have reduced the spark plug gap to .015 to get consistent spark. With the choke on it takes about 20 flips to get it to fire. After turning the choke off, it will fire up in about 10 flips and then quit due to what seems like a lack of fuel. Different needle settings don't seem to make any difference. Any suggestions would be appreciated. Thanks.