Re: [OMC-Boats] 2nd Shakedown Cruise

From: Lee Shuster (lib1) <lib1@...>
Date: Sun, 9 Aug 2009 09:26:59 -0600

What fun would old vehicles be if we weren't challenged with solving
electrical and fuel delivery glitches?

1) Scott is right-on. Our OMC hull designs are prone to porpoising and
"rougher" riding, due to rather shallow center-keel deadrise. His
approach with the ventilation/cavitation plate mounted foil is sound.
You can also add adjustable trim tabs.

2) As far as chasing fuel problems: All the filtration in the world
won't help if the source problem still exists. You'll potentially be
chasing your tail for years unless you go directly to the source: your
fuel tank and upstream fuel sources. The first step I take on any old
vehicle restoration is dropping or pulling the tank. It;s a no brainer
for me. See: or any local shop that performs
tank cleaning and re-lining. Even after you get rid of the obvious
stuff, the really fine, almost invisible rust-like crap will still
mess up a decent carb re-build. And remember each step in the fuel
delivery chain is affected: Carb: jets, float bowl, valve seats,
brass filters, Fuel pump: diaphragm, sediment bowl, Inline filters,
Cutoff-valves, copper lines, etc. Also install a modern canister
style, fuel filter/water separator while you're at it, they are pretty
much standard equipment on today's craft and available. Change the
canister once a season.

3) As far as your Prestolite Alternator: These come up on ebay once
in awhile. If you find one at a reasonable price, you can practice
rebuilding it yourself and you'll have spare. The are fairly simple
and easy to work on. If you search the internet under ALK-6207 or OMC
383443 you will find many of the parts are still available (including
the solid-state regulator) for this alternator thru BRP/OMC dealers,
amazingly. One nifty feature of this Prestolite-OMC design is the
external regulator is essentially water-cooled, by heat sinking the
regulator to the thermostat housing. With an internally regulated
alternator the solid-state electronics are exposed to higher operating
temps which can get quite high. especially if the alternator is
operated under heavier than normal duty cycles. Just remember to
have your ALK regulator checked out along with your ALK alternator.
The regulators rarely failed unless someone as incorrectly re-wired or
abused the system with a 2nd battery and switched the alternator under

4) As far as JD's quest for an oil sender switch: This is NOT a
MARINE-rated electrical part. Thus any number of vehicle application
use similar or identical switches. It only needs to have matching
mechanical threads. Just carry you old OMC part in and have them
eyeball it and hand you something that will physically fit.
Electrically it will most likely be 100% compatible. I believe this
part is also still carried by OMC/BRP dealers, but it is a little more
difficult to find, because only OMC Boats used the idiot light system.
When OMC sold the sterndrive package to OEM boatbuilders they used
"proper" water temp and oil pressure gauges, not idiot lights, thus
requiring different senders. In either case, it's all based on Stewart-
Warner technology dating back to the late 40's - early 50's. This
shouldn't be a big deal or show-stopping task!


On Aug 8, 2009, at 10:52 PM, Scott Veazie wrote:

> Hi Bill,
> I had the same problem with crud on my Seasport that I used to
> have. The easy solution I came up with was to install a second
> glass inline fuel filter. I put it immediately as the line exits
> the tank, and this in conjunction with one near the carb did a good
> job of trapped all the crap. It's not ideal, but after a while
> you'll get there.
> The second issue to mentioned I'm having as well on my 68 Seasport.
> Porpoising seems to be a common problem with these boats and lack of
> the ability to trim with the stern drive. The cheap and easy
> solution is to get a hydrofoil fin for the drive. I've had them
> before and they do wonders to kill porpoising, get you up on plane
> faster and at lower speeds, and cut fuel consumption. They
> literally do what the package says they do. I had doelfins the
> first time, but this time I'm going with the Sport SE 300. It costs
> more but is narrower and seems more rigid. I did a fair amount of
> research and it seemed to be the best. And for $60, it's well worth
> the investment.
> ~Scott
> Date: Sat, 8 Aug 2009 21:26:45 -0700
> From: bldfw@...
> To: omc-boats@...
> Subject: [OMC-Boats] 2nd Shakedown Cruise
> The first shakedown cruise of my Explorer brought to light the need
> for a carb rebuild and a tune up. I completed those though did have
> the problem with the ball bearing in the accelerator pump channel.
> Today was the 2nd shakedown which went really well. She started
> right up on the newly rebuilt carb. I was pleasantly surprised
> about that. Slow increase of the throttle brought smooth increase
> in power. I only pushed her to about 3000 rpm but she did get up up
> on plane. The lake had quite a bit of chop so I know what folks
> have been saying about the potential of being beat to death with a
> rough ride. will have to take her out a couple of more times to get
> used to it's behavior.
> Maybe it was the chop but it seemed to feel like it was porpoising
> or maybe I was over reacting to the new behavior.....anyone
> experience anything like that?
> I only encountered one significant problem that's easily
> resolved...crap in the gas tank. There wasn't a problem until we
> started to hit the chop which I'm sure stirred up crud sufficient to
> start flowing through the fuel lines. It first started happening at
> 2500rpm when it would take about 20secs before the fuel bowl would
> drain to the point of stalling. I checked the fuel filter (glass)
> and could see some crud in the filter. After a moment, it could be
> restarted and ran fine until 2500rpms again. No big deal.
> But then the longer we stayed out, the lower the rpms would get
> before it would stall. Eventually it got to where we could barely
> idle but fortunately we were on our way back to the marina.
> Continued fuel filter inspection showed the filter (glass type) was
> completely clogged with a pudding like substance. Will pull it
> tomorrow and check it closer.
> Other than that, the engine and outdrive appeared to run just fine.
> The next time I take her out I'll try pushing the rpm's past 3000k
> to see how she performs (when I have smoother water!).
> In the meantime, suggestions on best way to deal with the crud in
> the tank. I know the obvious is to remove the tank but having just
> rebuilt the interior of the boat, I'm not thrilled at the prospect
> of having to take it apart to get the tank out. I will if I have to
> but I thought I'd check with you guys to see of there's an
> alternative.
> Bill
> Dallas, TX
> 1970 Evinrude Explorer - 155 Buick V6 - OMC Sterndrive
> -Bill
> Get free photo software from Windows Live Click here.
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Received on Sunday, 9 August 2009

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