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

From: Jeff LaCoste <heavy@...>
Date: Mon, 4 Aug 2008 17:14:21 -0700

Agreed, thanks Ethan. I wish I could write such detailed and helpful
posts, wow!

Now I have my work cut out for me, I will let you all know what I
find out.


On Aug 4, 2008, at 4:45 PM, <lks@...> wrote:

> Nice overview & technical HOW-TO of the famous OMC Tilt motor and
> hammer-blow shock absorber, Ethan.
> When I first read only JEFF's Subject: "..Sterndrive motor drags.." I
> thought we would be reading about holeshots and drag racing I/O's ;)
> Lee
> PS -- This weekend I discovered how quickly an idling-ingear small
> block
> Chevy stops with it tangles with a ski rope. It's also nice that
> the tilt
> motor lifts the prop completely out of the water.
> I managed to get into the water with a sharp knive and free the
> rope without
> having to remove the prop. All in about 10 minutes!
> ----- Original Message -----
> From: "Ethan Brodsky" <brodskye@...>
> To: "Evinrude & Johnson Boats of the 1960's and 70's"
> <omc-boats@...>
> Sent: Monday, August 04, 2008 1:41 PM
> Subject: 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:
>> 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
>> --
>> Ethan Brodsky
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Received on Monday, 4 August 2008

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