Ok have a 97 merc 175 efi. Ever since I owned it, since 2005 it has never pee'ed well. When running prob get 12 psi, at idle 5 psi or less. Have had water pump changed every other year. Never had a over heating problem. I'm not really worried about it, but should I be? Prop hieght is 3.5" below pad. I do watch psi as trimming, and it never drops out.
On your engine, the telltale stream comes from the THERMOSTATS.
Hence, there would be little or no telltale stream UNTIL, or UNLESS the thermostats are OPEN.
Actual telltale stream strength varies.
Telltale water is HOT (do NOT stick your hands in it).
Water pump replacement (Annually) is a wise decision. Recommend ONLY OEM water pump components (Part# 96148A8 is a cost-effective, complete kit for your engine).
Water pressure (Minimum) Specs:
2-4 psi at IDLE
12+ psi at WOT (prefer to see 15+ for safe measure)
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