Re: [OMC-Boats] Looking at a 68 lower pump not working how hard to fix?

On Sat, 15 Jun 2013, Lin Holcomb wrote:
> So after about 10 sec the hose melted from the exhaust manifold to the
> intermediate housing. (sigh no water coming into the engine) Owner
> feels it is "Just the water pump in the lower unit". So a regular
> pump I can do no worries take a few $100 of the asking price every one
> is happy. Now lower water pump that is more of an issue.

I have exactly the same engine and outdrive in my 1970 Evinrude Explorer.
I've replaced the water pump in my lower unit twice since I bought it in
2004, once because I knew it was bad (overheating at idle) and once just
because I had everything apart and it seemed like a good thing to do. If
you are adept at automotive repairs then it will be a very easy process and
you can do it with just a standard set of hand tools. I've also done the
regular water pump on my Jeep and I would say the difficultly level is
comparable - access is easier on the boat because you're not jamming your
hands into tight spaces, but more difficult because you have to remove the
heavy outdrive.

You split the upper and lower part of the outdrive, and then the pump is
pretty much exposed. It's on the bottom of the upper portion of the
housing, so I believe you could leave that on the boat and tilt it up fully
for access, though both times I removed the entire outdrive from the boat
and did it on a workbench. It's probably easier that way because you can
turn the shafts then to simplify installing the pump. If you do remove the
outdrive, be very careful with the electric shift wire - it's easy to
damage it if you pull it before loosening it from the inside. Also pay a
lot of attention to how the swivel caps are assembled, as it's easy to put
them back together wrong.

I would recommend replacing the pump, housing, key, and cover plate. I
think a kit is still available from Sierra (West Marine, go2marine.com,
Amazon, ebay) for <$100. If you just want to do the rubber impeller, then
it's a lot cheaper, probably only $30 or so, but it looks like you are in
Minnesota, so it's very possible that your pump housing was damaged by
freezing at some point (mine was) and will be bent or cracked, so the kit
is nice to avoid worries about getting it apart and realizing you need to
order more parts.

While you have it apart, it's worth inspecting the splines on the pump
drive shaft, because I have been told that they are very prone to failure
(I just replaced mine even though they seemed fine - a new shaft can
usually be had for $30-70 on ebay). The service manual also recommends
inspecting the "swivel housing" and the remainder of the water pickup
system, because they are also prone to developing leaks that allow exhaust
in, causing the pump to fail.

The entire outdrive is very easy to service - OMC really understood
design-for-servicability back in the day (though perhaps that's just my
bias when compared to working on modern stuff that requires lots of
specialty tools).

I would also worry that other things might be damaged if he was running it
for some time with a marginal or failed water pump, but it's hard to say.

I found the SELOC service manual for the boat to be the best reference in
how to do it. I also have the Clymer manual and the original OMC dealer
service manual, but the SELOC is the best for this task. It's "OMC Stern
Drives 1964-1986 Repair Manual" and the relevant pages are 10-18 to 10-21
and 9-12 to 9-16.

Ethan Brodsky
Received on Saturday, 15 June 2013