[kevin boothe]

What is the usual time after start up for water to be discharged from this motor? Would having it at fast idle speed up the cooling or is there a thermostat controlling the cooling?

[fishingdan]

What year is the engine?

Do a search. You'll find several discussions on the cooling system for these engines.

It is hard to answer your question. I know on my 1982 150, I get a dribble (barely) after about 15 seconds. On my engine, water only gets to the tell-tale when the t-stats open. It will get a weak stream after running hard, but then it will reduce to a dribble again after idling a bit.

In general, I would say 15 seconds is a good number.

[wilde1j]

My '95 150's took about 30 to 60 seconds to have water come out of the telltale port. This really doesn't tell much, other than the water pump is working (sort of), so I wouldn't get my shorts twisted in any case. My Merc discharged from the end of the cooling cycle and the water was normally pretty hot coming out.

[kevin boothe]

Jim My 150 is a 1992 I get a good stream after about 30 -45 seconds and runs in the middle of the temp gauge on a 180 procraft