???? Duplicate Post ???? You were told in another post here where that hose should be attached... a fitting at the lower main bearing area.
Flush engine in a tank with saltaway, Have you run a compression test on her ? Was the water tube leading from pump to powerhead inspected? Was waterpump
That screw would either have made it to the related cylinder and have been blown out the exhaust port... OR... more likely, be jammed in the related reed
Install tape in a clockwise direction around upper 3/4 portion of threads
Found that on a 135 hp many years ago.---Stuck in the reeds.----Found the same thing on a big twin, stuck in the reeds