1997 2 Stroke 150 (S150TXRV) Power Head Passages Description/Function

[BoatMon345]

I have been trying to diagnose a cooling problem with my 1997 2 stroke 150 (S150TXRV), and it would greatly help me if I could better understand exactly the function of each of the following passages on my powerhead and its mating surface. I've checked my manual but cannot find such description:







Passage 1=?
Passage 2=?
Passage 3=Poppet/pressure valve water exit to midsection
Passage 4=?
Passage 5=Starboard Exhaust
Passage 6=Port Exhaust
Passage 7=?

Thanks much.