On 5/22/2013 10:10 AM, Eisboch wrote:


"John H" wrote in message
...

On Tue, 21 May 2013 20:41:39 -0400, Wayne B
wrote:

On Tue, 21 May 2013 02:55:41 -0400, "Eisboch" wrote:



"Rupp0003" wrote in message ...


1989 merc 3.0 starts fine, runs fine for about half an hour at any
speed
or rpm then starts to miss and will eventually stall. Fuel dripping
from
flame arrestor but only once rough running starts. Will sometimes
restart after a few minutes and run ok other times will continue to
run
rough and stall.

Are there any members out there that might have some insight into what
the problem might be?

--------------------------------------------------------------------


Bad coil. (Goes bad when warm .... ok when cold.)

====

Probably right. I had that problem on one of my old 454s. To make
it worse, some genius decided that the coil should be mounted very
near the exhaust manifold.


The dummies who built my old Proline put the live well right above the
coil, with no sealant. Took
me two coils to figure out where the problem was.

I think Eisboch nailed it. At the price of coils, it's well worth giving
a replacement a try.

John H.

----------------------------------------

Maybe. Educated guess due to similar experience. The fact that the OP
says it runs fine at any speed for about half an hour makes me think
it's probably not carburetor related. Sounds more like something heats
up and fails which is more likely an ignition problem and the coil
(especially if it's older) is suspect.

Had the same thing happen one morning on the old '82 Century. Mrs.E.
and I were taking a ride up to Boston Harbor from Scituate. It was
probably just about in the same timeframe that the engine sputtered and
died, right in the path of one of the Boston to Provincetown high speed
boats that was just getting up on it's hydrofoils. It blew by us in a
rush with it's horn blaring. After sitting dead in the water for a
while the coil cooled off enough to restart the engine and we limped our
way slowly back to Scituate at idle speed.


I wouldn't put money on any of the suggested diagnosis, including mine,
but it would be worth checking out all of them. Most of the coil
overheating problems show visual signs like bulging or oil under the
high tension lead. Carrying a spare would be good insurance.

On Wed, 22 May 2013 11:46:18 -0400, Hank©
wrote:

I wouldn't put money on any of the suggested diagnosis, including mine,
but it would be worth checking out all of them. Most of the coil
overheating problems show visual signs like bulging or oil under the
high tension lead. Carrying a spare would be good insurance.

======

The intermittent coil on my old 454 showed no external symptoms at
all. The engine had failed several times previously after it had been
run for a while but on the last occasion I was able to prove that
there was no spark even though the coil primary showed that the
voltage was being properly interrupted.

"Hank©" wrote in message
eb.com...

On 5/22/2013 10:10 AM, Eisboch wrote:


"John H" wrote in message
...

On Tue, 21 May 2013 20:41:39 -0400, Wayne B
wrote:

On Tue, 21 May 2013 02:55:41 -0400, "Eisboch"
wrote:



"Rupp0003" wrote in message
...


1989 merc 3.0 starts fine, runs fine for about half an hour at any
speed
or rpm then starts to miss and will eventually stall. Fuel
dripping
from
flame arrestor but only once rough running starts. Will sometimes
restart after a few minutes and run ok other times will continue
to
run
rough and stall.

Are there any members out there that might have some insight into
what
the problem might be?

--------------------------------------------------------------------


Bad coil. (Goes bad when warm .... ok when cold.)

====

Probably right. I had that problem on one of my old 454s. To
make
it worse, some genius decided that the coil should be mounted very
near the exhaust manifold.


The dummies who built my old Proline put the live well right above
the
coil, with no sealant. Took
me two coils to figure out where the problem was.

I think Eisboch nailed it. At the price of coils, it's well worth
giving
a replacement a try.

John H.

----------------------------------------

Maybe. Educated guess due to similar experience. The fact that
the OP
says it runs fine at any speed for about half an hour makes me think
it's probably not carburetor related. Sounds more like something
heats
up and fails which is more likely an ignition problem and the coil
(especially if it's older) is suspect.

Had the same thing happen one morning on the old '82 Century.
Mrs.E.
and I were taking a ride up to Boston Harbor from Scituate. It was
probably just about in the same timeframe that the engine sputtered
and
died, right in the path of one of the Boston to Provincetown high
speed
boats that was just getting up on it's hydrofoils. It blew by us
in a
rush with it's horn blaring. After sitting dead in the water for a
while the coil cooled off enough to restart the engine and we limped
our
way slowly back to Scituate at idle speed.


I wouldn't put money on any of the suggested diagnosis, including
mine,
but it would be worth checking out all of them. Most of the coil
overheating problems show visual signs like bulging or oil under the
high tension lead. Carrying a spare would be good insurance.

----------------------------------------

You're right of course but the OP's description of how the engine was
acting sound VERY familiar. I was having the symptoms for a week or
two (ran ok cold, started getting rough when warmed up and was very
evident when I tried to push that tank of a boat up on a plane after
being warmed up. I think you were still around here after the Boston
Harbor experience. When it died that time, it blew the high tension
wire right out of it's seat and indeed, there was oil on the coil.
But, after it cooled down for a while, it worked enough to putt-putt
back to Scituate. New coil fixed *that* problem and we moved onto
the next one.
That boat should have been retired from service years before. :-)

All this is familiar to me as I had similar problems with the 25 hp Johnson on the Princecraft Yukon.
Screws had worked loose and tore up the stator.
Since I wasn't using it for charging, I had the service tech remove the bad parts and the outboard worked perfectly until I traded the boat in a year ago.

On 5/22/2013 5:20 PM, Eisboch wrote:


"Hank©" wrote in message
eb.com...

On 5/22/2013 10:10 AM, Eisboch wrote:


"John H" wrote in message
...

On Tue, 21 May 2013 20:41:39 -0400, Wayne B
wrote:

On Tue, 21 May 2013 02:55:41 -0400, "Eisboch" wrote:



"Rupp0003" wrote in message ...


1989 merc 3.0 starts fine, runs fine for about half an hour at any
speed
or rpm then starts to miss and will eventually stall. Fuel dripping
from
flame arrestor but only once rough running starts. Will sometimes
restart after a few minutes and run ok other times will continue to
run
rough and stall.

Are there any members out there that might have some insight into what
the problem might be?

--------------------------------------------------------------------


Bad coil. (Goes bad when warm .... ok when cold.)

====

Probably right. I had that problem on one of my old 454s. To make
it worse, some genius decided that the coil should be mounted very
near the exhaust manifold.


The dummies who built my old Proline put the live well right above the
coil, with no sealant. Took
me two coils to figure out where the problem was.

I think Eisboch nailed it. At the price of coils, it's well worth giving
a replacement a try.

John H.

----------------------------------------

Maybe. Educated guess due to similar experience. The fact that the OP
says it runs fine at any speed for about half an hour makes me think
it's probably not carburetor related. Sounds more like something heats
up and fails which is more likely an ignition problem and the coil
(especially if it's older) is suspect.

Had the same thing happen one morning on the old '82 Century. Mrs.E.
and I were taking a ride up to Boston Harbor from Scituate. It was
probably just about in the same timeframe that the engine sputtered and
died, right in the path of one of the Boston to Provincetown high speed
boats that was just getting up on it's hydrofoils. It blew by us in a
rush with it's horn blaring. After sitting dead in the water for a
while the coil cooled off enough to restart the engine and we limped our
way slowly back to Scituate at idle speed.


I wouldn't put money on any of the suggested diagnosis, including mine,
but it would be worth checking out all of them. Most of the coil
overheating problems show visual signs like bulging or oil under the
high tension lead. Carrying a spare would be good insurance.

----------------------------------------

You're right of course but the OP's description of how the engine was
acting sound VERY familiar. I was having the symptoms for a week or
two (ran ok cold, started getting rough when warmed up and was very
evident when I tried to push that tank of a boat up on a plane after
being warmed up. I think you were still around here after the Boston
Harbor experience. When it died that time, it blew the high tension
wire right out of it's seat and indeed, there was oil on the coil. But,
after it cooled down for a while, it worked enough to putt-putt back to
Scituate. New coil fixed *that* problem and we moved onto the next one.
That boat should have been retired from service years before. :-)

He had a symptom that you didn't have.

Ask Harry if he went to the Navy Seal museum just down the street from
the Disney resort he stayed at. They had some pretty interesting old
boats on display.

"Hank©" wrote in message
b.com...

On 5/22/2013 5:20 PM, Eisboch wrote:


"Hank©" wrote in message
eb.com...

On 5/22/2013 10:10 AM, Eisboch wrote:


"John H" wrote in message
...

On Tue, 21 May 2013 20:41:39 -0400, Wayne B
wrote:

On Tue, 21 May 2013 02:55:41 -0400, "Eisboch"
wrote:



"Rupp0003" wrote in message
...


1989 merc 3.0 starts fine, runs fine for about half an hour at
any
speed
or rpm then starts to miss and will eventually stall. Fuel
dripping
from
flame arrestor but only once rough running starts. Will sometimes
restart after a few minutes and run ok other times will continue
to
run
rough and stall.

Are there any members out there that might have some insight into
what
the problem might be?

--------------------------------------------------------------------


Bad coil. (Goes bad when warm .... ok when cold.)

====

Probably right. I had that problem on one of my old 454s. To
make
it worse, some genius decided that the coil should be mounted very
near the exhaust manifold.


The dummies who built my old Proline put the live well right above
the
coil, with no sealant. Took
me two coils to figure out where the problem was.

I think Eisboch nailed it. At the price of coils, it's well worth
giving
a replacement a try.

John H.

----------------------------------------

Maybe. Educated guess due to similar experience. The fact that
the OP
says it runs fine at any speed for about half an hour makes me
think
it's probably not carburetor related. Sounds more like something
heats
up and fails which is more likely an ignition problem and the coil
(especially if it's older) is suspect.

Had the same thing happen one morning on the old '82 Century.
Mrs.E.
and I were taking a ride up to Boston Harbor from Scituate. It was
probably just about in the same timeframe that the engine sputtered
and
died, right in the path of one of the Boston to Provincetown high
speed
boats that was just getting up on it's hydrofoils. It blew by us
in a
rush with it's horn blaring. After sitting dead in the water for
a
while the coil cooled off enough to restart the engine and we
limped our
way slowly back to Scituate at idle speed.


I wouldn't put money on any of the suggested diagnosis, including
mine,
but it would be worth checking out all of them. Most of the coil
overheating problems show visual signs like bulging or oil under the
high tension lead. Carrying a spare would be good insurance.

----------------------------------------

You're right of course but the OP's description of how the engine
was
acting sound VERY familiar. I was having the symptoms for a week
or
two (ran ok cold, started getting rough when warmed up and was very
evident when I tried to push that tank of a boat up on a plane after
being warmed up. I think you were still around here after the
Boston
Harbor experience. When it died that time, it blew the high
tension
wire right out of it's seat and indeed, there was oil on the coil.
But,
after it cooled down for a while, it worked enough to putt-putt back
to
Scituate. New coil fixed *that* problem and we moved onto the
next one.
That boat should have been retired from service years before. :-)

He had a symptom that you didn't have.

Ask Harry if he went to the Navy Seal museum just down the street from
the Disney resort he stayed at. They had some pretty interesting old
boats on display.

-----------------------------------------

You mean gas in the flame arrester? I don't remember it being like
that but I *do* remember smelling gas due to the carb becoming flooded
after several attempts to start it without success. That was before
realizing the high tension wire had blown off the coil.

I had the same problem with my '88 OMC Cobra, I changed the coil &
condenser, problem solved, has been fine ever since.

Happy boating, Norm