Does it really have good compression? You may also try a different plug, or like one of my Fox 15's, flood it to start. Each engine has it own character, even in same brand and size. By the way if engine is inverted, which I think the Score is. Turn the plane over before starting or even fueling the tank. Prime the engine and flip the prop. If it flips real easy, then hook up the battery and see if you get a bump. If so flip it and it should start and run the prime out. Then I usually prime again and start it again. Then turn the plane over, fill the tank, make sure fuel is to needle valve, hook up battery and see if you get a bump. If it bumps it should start fairly easy. My method I learned from someone else. Thanks Bigiron. Have fun, DOC Holliday