"Dave" <Dave@[EMAIL PROTECTED]
> wrote in message
news:k8ev54dsrfkvfu8pnnh57kf26l3s5vj9tp@[EMAIL PROTECTED]
> My 2 1/2 hp 2 cycle dinghy motor, a Mariner (Mercury under a different
> name
> I believe), has begun to exhibit some strange behavior. It starts
> perfectly
> fine, generally on the first or second pull, runs normally for about 4
or
> 5
> minutes, and then gradually slows and stops. Pull the starter cord, and
it
> starts right up and repeats the behavior.
>
> At first I thought it might be the vent partially plugged, creating a
> vacuum
> in the tank as the motor ran, but running the engine with an unscrewed
> filler cap didn't change the behavior.
>
> Any thoughts as to what might be causing the problem? This is the first
> time
> I've run it since last season, and at that time it wasn't exhibiting
this
> behavior. Another point of reference: while I filled the tank with fresh
> fuel before starting this year, I hadn't run the engine dry before
storing
> it for the winter, so some fuel probably remained in the fuel system
over
> the winter.
Don't even listen to those other idiots who chimed in with the same old
lame
information. Listen to me, Wilbur Hubbard, because, as usual, I have all
the
right answers.
You were on the right track with thinking it had something to do with the
tank vent. It has everything to do with the tank vent.
There is a rubber seal of sorts, sort of a domed looking affair, under the
little thumb screw inside the tank cap. When the vent is screwed down,
especially for an extended period of time, the rubber diaphragm gets
flattened and it tends to bind up around the central screw shaft of the
vent
screw mechanism. Even when you open the vent sometimes it does not let any
air pass. What you have to do then is unscrew the cap itself and you will
undoubtedly hear a hiss as air p***** into the tank. the motor will then
run
normally until such time as a vacuum builds up inside the tank again. What
you need to do is exercise the vent screw back and forth back and forth
until the rubber washer loosens it's grip on the screw mechanism from
being
compressed which effectively makes the hole in the center a smaller
diameter.
I have a Mariner 3.3 which is the same engine with a N-R ****fter and the
restrictor washer in the carb throat removed. (If you want to make yours
the
same power as a 3.3 just remove the carb and take out the washer you will
find in the intake track then raise the jet needle by lowering the c-clip
one or two notches) and it has exhibited those symptoms for a couple of
years now. I'm too cheap to buy a new cap so I just live with it.
You're welcome.
Wilbur Hubbard
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