The hardest part is getting the short rubber hose loose from the riser especially with captains choice so close to the riser. If you have the time & tools to mess with it you can save some $$. If not let a shop do it. Randy

You may want to unscrew the oil fill cap or take off a valve cover breather and look into the engine for any milky colored oil. When my buddies boat riser started leaking you could see a collection of milky looking moisture building up under his oil fill cap. On a side note when we changed his manifolds and risers with brand new ones it initially leaked at the same spot as yours until we tightened the bolts down even more. It's possible you may just need a new gasket and tighten the bolts but I'd defintely take a close look at things since it can trash an engine real quick.