Re: [OMC-Boats] OMC-Boats - Sterndrive motor drags

On Mon, 4 Aug 2008, Jeff LaCoste wrote:
> Recently my stern drive on my OMC 64 Deluxe started to refuse to drop
> down or raise itself without a little helping hand from me. I
> remember hearing that the gear/motor for these were a little lacking
> on the power. Has anyone on the list experienced this? If so did you
> fix the unit or replace it? Any idea on the costs of these? I think I
> could probably get one as SeaWay in Seattle.

The first thing to do is check the oil in the tilt gearbox. The oil fill
point is the plug in the lower center of your picture. Pull it off and
hopefully there will be oil to that level - or if it's like mine it'll be
filled to the top with a milky oil water mixture. Either way, squirt some
oil in (I've seen various opinions as to whether 10W30 or Type C is
recommended) and work it up and down a few times.

Replacing the tilt motor is a fairly simple process, though may be somewhat
difficult to reach and might require a good set of tools. I needed to
modify a hex driver bit to do the inner bolt, as clearance is blocked by
the bell housing. That's on a '70 with the 155 hp V-6 - yours might be
different. I'm guessing this wouldn't be a problem with a better tools.

If you've got the same innards as me, the tilt motor is a Prestolite
ETK4102 - I bought mine refurbished for $100 from Finicki's Auto Electric,
a local shop (they had it in-stock and, yes, it was marine-rated!). I've
seen new ones on ebay for as little as $30, though that requires more
patience. They are widely available online for $75-150 or so:
  http://www.google.com/search?q=etk4102

If you have it apart, I'd recommend replacing the "hammer-blow coupler" as
well - I bought mine from Seaway (#309267) for about $7 shipped. You might
destroy the old coupler while removing it, so once you decide to do this
you're somewhat committed.

Be careful while installing the new motor - the mounting bolts hold the
motor end-cap on, so if you tilt it the wrong way, it'll all fall apart.
There's probably some pro trick like using tape to hold it together during
installation, but I didn't know that. It's pretty annoying to have to fish
all the little parts (brushes, springs, gaskets, wave washers, etc...) out
of the bilge, and I'm sure getting them wet wasn't great for them. If I
had had the right tools and wasn't an idiot about letting it fall apart, I
think the swap would've only taken about 15 minutes. Instead I spent about
an hour, as I had to do one of the bolts with an open-ended wrench in tiny
increments.

My old motor was badly corroded inside - I can't remember if I had to
return it as a core or if I still have it around, but it didn't look worth
fixing.

Replacing the tilt motor led to an immediate and vast improvement in tilt
performance. It'd been lethargic as long as I'd had the boat and sometimes
needed some help, especially if the battery was low or it was cold. Now it
instantly flies up and down, so quickly that it often will go all the way
to the lower bump stop from a brief push - I've thought of adding an inline
resistor to the down relay to make it drop slower.

You didn't mention anything about this, but one other thing that can cause
bad tilt performance is improper clearance in the tilt gearbox. Over the
winter, I reassembled mine without the gasket (used silicone instead),
making it perhaps 0.3 mm thinner, and it would no longer move at all. I
had to take it apart again and reinstall the gasket - the preload on the
clutch is crucial to making it move properly.

Hope this helps,

Ethan Brodsky

-- 
<a href="http://www.engr.wisc.edu/~brodskye/"> Ethan Brodsky </a>