I am running in fresh water (St. Lawrence 1000 Islands area) and it is not a
closed system (no antifreeze). My boating habits rarely take me into silty
/ dirty water, but maybe the zebra mussels that have invaded the area and
cleaned up the water have managed to get hold of my system. I have never
run the boat dry and do not even turn the engine over without muffs on.
Another boating friend insists it is the pump in the outdrive that is the
trouble and has offerred to assist changing it this time.

The reason I am suspecting the outdrive pump is the "so called" mechanic
that replaced it for me last year somehow managed to reassemble the drive
without a spacer / washer that can fall out when the drive is split. That
washer missing caused no symtoms for about a month or two and then
periodically caused an inability to shift. I contacted a more reputable
mechanic and he diagnosed the problem for me over the phone and had my boat
fixed back up the same day.

Some great feedback and suggestions everyone.

Mark (the rail & canopy hook guy)
www.ripnet.com/vtf/prod03.htm

"Len Krauss" wrote in message
...
You don't say whether you operate in fresh or salt water, or whether your
engine has fresh water w/anti-freeze circulating coolant (w/ heat
exchanger). Esp if it's operated in salt water, on a '86 boat, I'd bet on
the riser being clogged. Pull it and have a look -- you'll need new
gaskets
when making replacement. You can "rod it out" or have a radiator shop give
it an acid cleaning -- either will give you just one or two seasons more.
Usually better to buy new if you intend to keep the boat.

First choice would have been lower unit pump impeller, but that's fairly
new -- unless it was later run dry and damaged. Impellers should be
changed
every three years or so for normal recreational boats. The rubber gets
stiff
with age and they lose efficiency. In water with lots of silt and
particulates, esp frequent shallow water operation, they can wear out
faster
due to abrasion. Same for the metal contact surface in the pump --
inspection will tell if that (or more likely) the whole pump needs
replaced.

Good luck,
Len

Eliminate "ns" for email address.

--
"Mark" wrote in message
sgroups.com...
I have a 350 with an Alpha 1 that is overheating at low rpms.
Diagnosing
the same problem last year, I had to have the water pump in the lower
unit
replaced. I will troubleshoot all other possibilities this weekend
before
having to pull the boat out, but thought you folks in the news groups may
have some ideas as to what other causes it could be.

The boat is an 86 and I have owned it for about ten years for having to
replace the outdrive water pump. Any estimates as to what the life
expectancy of the water pump should be?

First I will be checking for leaks, then changing the t'stat on the
engine
(as I do not recall when I last replaced it), but beyond that, Ican only
suspect either the new (last year) pump has failed prematurely, or the
mechanic I hired to do it did.

Mark (the rail & canopy hook guy)
www.ripnet.com/vtf/prod03.htm