2002 volvo penta 5.7 gi a overheating

[Stuart 177]

2002 VP 5.7 GI A raw water cooled salt water. New manifolds,risers, water pump, lower inlet fitting. Six cyl have 215 psi and two have 180 psi. Idles smooth on muffs but overheats after 5 minutes. Overheats fast under throttle and load in water. Loopy idle in neutral at dock in water. 1200 rpm in gear at dock no overheat. Noise in out drive in water goes away after 2000 rpm

 

[Stuart 177]

Collapsing inlet hoses, intake water system air leak, bad head gaskets, restricted exhaust gas, PS cooler clogged? Water pumps out well with muffs. Thinking of thru hull water pick up new long block. Boat sat in salt water for ten years in ny. Poorly maintained by prior owner.