To little compression can easily mean no fuel loaded in the cylinder Which further 'motivates' my theory. My ST 1.40 did this the other day having not run for a while. Simply switch plugs and richen the high and low needles some. You may have already tried this, but it's worth it to try again if it saves you a new engine. If the engine is being spooled very fast and just ups and dies it's lean. If it stutters then dies, rich. Also, my ST tends to not catch every once and a while. And if I very slowly advance the throttle I can find where it sags, leave it there for a bit and see if it eventually catches, if not richen the mixture..


Cheers