wierd, i just got the same engine it looks like. mine was off of a pro mac III weed whacker. i had the same issue. there is a bolt in the center of the shaft, heres the catch. the shaft that the clutch is on is not the crank shaft. rather it is a extension piece threaded onto the crank. find a way to hold the flywheel and turn the clutch assembely. or you could do what i did. i got pi$$ed off and drilled the bolt head off the clutch which made everything real easy to get apart and did not damage any important parts. it looks in the pic like you got as mad as me. i would have just unscrewed the bolt but mine was all rounded out so that was not an option. hope this helps.