You push the outer wheel in and it locks the bigger flywheel onto the shaft to start what ever is belted to the flywheel. This thing is very interesting and well made. And then picks it up in person. The item “Clutch shaft unit removed from Hit Miss Woodpecker Engine Middle Town Machine” is in sale since Friday, July 03, 2015. This item is in the category “Business & Industrial\Light Equipment & Tools\Stationary Engines\Parts”. The seller is “mrbubblesupplycheap” and is located in Branchville, New Jersey. This item can’t be shipped, the buyer must pick up the item.