250 OX66 No Tell Tale?

I have twin 2000 250 OX66s. Water pumps and impellers replaced October 2008. This past weekend 1 motor would not "pee" at start up. I only gave the motor abour 3mins and shut down, but no overheat alarm sounded. Very briefly rasied RPMs to 1200 and still nothing. Prior to shut down I briefly disconnected the flush connection on the side of the motor and noted good water flow.

After shut down I used the flush connector on the hose and motor did not pee. I heard a pressure/gurgle sound coming form somewhere in the powerhead.

Seems pretty obvious to me I have an obstruction of some kind in the cooling passages. Agreed?

If so, my question is how can I dislodge? Remove thermostats and poppit valve and run on hose? Try with just saltway system etc.?

I'll appreciate any help I can get. Thank you.

[robert graham]

about once a year or so a mud-dauber/wasp will puck mud up in the pee hole on my Yamaha 90HP, just a piece of wire/coat hanger or other to unplug the hole. you can also put your garden hose on the pee-hole outlet and try to back-flush it. hope it works out that simple for you! Good luck.