canadianjack wrote:
Its a fresh water system ... the boat/motor runs quite strong so timing
is good however your point on the flushing is good! I havent had that
looked at. would a flush clean things out or is there parts
replacement necessary? thanks you've been very helpful ....

Larry wrote:
"canadianjack" wrote in
oups.com:

I have a 1987 Formula 223 with a 350 merc mag (approx. 390 hrs) and
I've replaced the thermostat and impeller because it was overheating to
over 200 degrees. The Thermostat did not solve the problem so I changed
the impeller in the outdrive and the problem is still there.

It runs at about 160degrees at idle and then at high speed (40/50 mph)
its still comes down to 160 degrees ... but at the middle speeds, with
trim lowered, making turns, slowing down etc temp will reach
200degrees? my oil is pumping at approx 30lbs ... I checked the oil,
the gauge seems to work fine ( i checked the ground to it and it
works?) ... wondering what temp the boat should run at ( i thought
approx 160degrees)? any ideas or suggestions? much appreciated.



Salt water or fresh? Directly cooled or heat exchanger? I see you're in
Canada, so water temperature isn't much of an issue...unless someone
wants to go swimming, as I remember..(c;

Does the boat seem to have as much power as it always did or does it feel
like it's lagging behind what it used to do? That would indicate,
probably, a timing problem, which will make them heat up.

87 to 2006 is quite a few YEARS sitting there all winter corroding up in
the cooling system of a fresh-water cooled block. Has anyone pulled a
head off to see what the cooling passages look like inside after all this
time? Imagine running your car V-8 on just water since 1987. Think
it'll need some serious "flushing" if it never had antifreeze in it, just
rusty water?

--
There's amazing intelligence in the Universe.
You can tell because none of them ever called Earth.

You might want to replace the hose between the water pick up and the
water pump. That hose is basically a hose within a hose, and it's on
the suction side. The inner hose can colapse, restricting water flow.
Try checking the water inlets as well, make sure their clean. The heat
exchanger could be clogged, pull the end caps off and very carefully
run a narrow wire in and out of all the passages. Check the oil cooler
as well (if it has one) it could restrict the system.