How to sell my blown engine

[Aquaholic101]

I need to sell my blown engine. This may sound like a silly question. I will be selling it to a shop that rebuilds engines, do I just pull up my boat to the shop and they pull it off? The marina that is putting on the new engine is charging me 3 hrs of labor to remove the old engine and they don't take trades so I figure should I yank it off myself and bring it to the shop or let them pull it off. If they take it off should I expect they will charge me and take it off the price they are giving me for the engine?