Laguna powerboat report

[Chuck]

With about 600 lbs of folks aboard, I learned a few things yesterday.
The most important was that my 5 horse OB would not go above about 2/3
throttle. Maybe someone can give me some hints about what to look at.
It starts easily idles just fine. When you throttle up, it goes
smoothly up to a point and then, though you continue to twist the
grip, it tops out at some point and is somewhat variable there. If you
crank it down to just below that point, it is steady in rpm's but all
the way up it is slightly wavery - I don't know how else to put it.
It does not vary dramatically, but it varies a bit until you back it
off.

Anyway, with the 2 horse, I got 4.5 mph at high idle (where the
centrifugal clutch engages), 5.5 at mid-throttle and 6.5 at WOT. The
Five horse got 5.5 at high idle, 6.5 at about half throttle and 7,5
where it stopped going up. I feel sure I would have got 8 if the
thing had gone all the way.

Now I need to fix the 5 horse and do some mileage tests. What I want
to know is if I choose a desired speed of 6 mph, will I get better
economy with the 2 horse ob at a higher throttle setting or with the 5
horse at a lower setting? Also, what is a good way to check the
mileage on the 5 horse motor with it's external tank? Do I have to
hook a graduated cylinder to the fuel line? For the 2 horse, I can
pour a measured amount of gas into the tank and run it dry.

Chuck

[AndrewL]

On the engines always work on Mythbusters, you know.

For the gas test, do you think you can fill the tank to a known
amount, motor around for a couple hours, then measure out how much it
takes to fill it back up again?

[Chuck Leinweber]

I can do that with the little one - it has an integrated tank. But the 5
horse with the 3 gallon not attached, I am not sure how to get an accurate
measurement. I guess I will have to go back and read Rob's column on the
subject:
http://www.duckworksmagazine.com/08/columns/rob/index7.htm

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[OconeePirate]

On Jul 26, 9:13 am, Chuck <chuck.leinwe...@gmail.com> wrote:
> With about 600 lbs of folks aboard, I learned a few things yesterday.
> The most important was that my 5 horse OB would not go above about 2/3
> throttle. Maybe someone can give me some hints about what to look at.
> It starts easily idles just fine. When you throttle up, it goes
> smoothly up to a point and then, though you continue to twist the
> grip, it tops out at some point and is somewhat variable there. If you
> crank it down to just below that point, it is steady in rpm's but all
> the way up it is slightly wavery - I don't know  how else to put it.
> It does not vary dramatically, but it varies a bit until you back it
> off.
>

Have you checked air flow and fuel flow to the engine? Clogged fuel
filter, crimped fuel line could both give that kind of results, as
would a severely dirtied air filter.

I don't know anything about how outboard motors are put together. In
a car at that point if fuel and air are fine you start looking at
fire. Ignition timing, points gaps, coil condition, that kind of
thing.

[Chuck Leinweber]

I did check the fuel filter and the spark plug. I'll look at the air filter
next. Thanks!
Chuck

-----Original Message-----
From: michalak...@googlegroups.com
[mailto:michalak...@googlegroups.com] On Behalf Of OconeePirate
Sent: Monday, July 26, 2010 10:19 AM
To: Michalak's Laguna
Subject: Re: Laguna powerboat report

--

[jhargrov...@juno.com]

Chuck,
Sounds like you have a fuel air mixture adjustment to make.  It is running too lean.  I am not familiar with your engine so, do you have an adjustment handy for the high speed jet?  Crank it and open up the throttle all  the way and turn it counter clockwise until it slows down from running too rich then turn it clockwise until it speeds up to a maximum speed then back off about an 1/8th turn.  Or just read the directions if you still have them.
john wright