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

From: lks@...
Date: Mon, 4 Aug 2008 17:45:03 -0600

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 ;)


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"
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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> OMC-Boats@...
Received on Monday, 4 August 2008

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