Water Tube Seal Fell Out During Pump Change

I am doing a water pump replacement on a 30 horse model elrv, the water tube pulled out during the install and the rubber seal on top of the tube fell out. There are actually two seals on top of the water tube, but they are behind a metal plate which I cannot get access to, the water tube passes thru this plate and the tube is protected by a rubber grommet then at the top of the tube is another rubber seal that then plugs into the upper water passage. The seal that fell off is #2 in the parts diagram, Yamaha part #6j8-44366-00-00. I cannot figure out how to get this seal back on the tube and connected behind the metal plate because the hole is too small to pass said seal thru. This seal originally fell out thru another different small opening, I'm not sure if this means that I have to pull the powerhead to gain access to the top side off the transition point in the middle casing. Here is a link to said motor diagram



http://www.marineengine.com/parts/yamaha-outboard-parts/1997/30/30ELRV/620301630016