Mariner drain in floor?

[JayRay]

I have a '71 mariner and one of the drains in the cockpit floor doesn't seem to work (water won't drain out). How do you fix it?

 

[callnab]

Mariner Cockpit drains

I had trhe same problem this spring when I uncovered from Winter wrap.I found the holes plugged with debris down in the curved hose connecint the drain to the fitting in the hull.I used may hand Bilge Pump placed firmly over the cockpit drain and it suched the debris out with the water and has been fine since.