Losing Power on I/O

[Sixeye]

I have an I/O with an OMC 4.3 liter V6. Last time out, about a month ago, I
was losing power any time I got up to about 25 mph or when pulling a
wakeboarder. I could pull the boarder up and get to speed but within about
30 seconds, the engine would sputter and lose power, completely stalling if
I didn't back off the gas.

While driving with no load (no boarder, that is), I could do fine to about
23 mph but as soon as I hit 25 or so, the engine would sputter again.

Does anyone have any suggestions on what I should look for?

[Awsome]

It could be any thing ...

I think you should check your carburator tuning or a leakage of air cauz at
low RPM it works fine with or without load but sputter at high RPM means
could be a air leakage some where in carburator seal.
Second look for some short spark plug, that could be another possibility.
I am not sure if your distributor is equiped with a capacitor usually it is
hidden iside the distributor, check if it is not faulty.

Post by Sixeye
I have an I/O with an OMC 4.3 liter V6. Last time out, about a month ago,
I was losing power any time I got up to about 25 mph or when pulling a
wakeboarder. I could pull the boarder up and get to speed but within about
30 seconds, the engine would sputter and lose power, completely stalling if
I didn't back off the gas.
While driving with no load (no boarder, that is), I could do fine to about
23 mph but as soon as I hit 25 or so, the engine would sputter again.
Does anyone have any suggestions on what I should look for?

[Sixeye]

Thanks. I'm not sure what you mean by a "short spark plug". I did replace
all of the plugs today.

One thing I noticed is that the plastic fuel line between the fuel pump and
the carb is attached at either end using tywraps (wow, how high tech!). The
tywrap at the carb end had broken off. I wonder if maybe that seal was
enough to not leak fuel but enough to let air in under load?

I also inspected under the distributor cap and saw that all the contacts
were in pristine condition. I believe there is indeed a capacitor in there
but I wasn't looking for it. And the points seemed to be okay (without
removing them to inspect).

I'm going to pull the boat out of my garage and run it next weekend to
circulate the Stabil I poured in today. Before I run it, I'll check the
bolts to make sure the carb is secured tightly, and look for other
possibilities of air leakage.

What should I be looking for when I inspect the capacitor in the
distributor? Maybe I should just replace it. If I remember right, the
capacitor is to prevent arcing across the points.
--

Post by Awsome
It could be any thing ...
I think you should check your carburator tuning or a leakage of air cauz
at low RPM it works fine with or without load but sputter at high RPM
means could be a air leakage some where in carburator seal.
Second look for some short spark plug, that could be another possibility.
I am not sure if your distributor is equiped with a capacitor usually it
is hidden iside the distributor, check if it is not faulty.

Post by Sixeye
I have an I/O with an OMC 4.3 liter V6. Last time out, about a month ago,
I was losing power any time I got up to about 25 mph or when pulling a
wakeboarder. I could pull the boarder up and get to speed but within
about 30 seconds, the engine would sputter and lose power, completely
stalling if I didn't back off the gas.
While driving with no load (no boarder, that is), I could do fine to
about 23 mph but as soon as I hit 25 or so, the engine would sputter
again.
Does anyone have any suggestions on what I should look for?

[Awsome]

May be your engine needs a simple tune up.

Secondly check the old spark plugs if any oil or carbon mark on any one of
them. There color should be light grey on tips if ignition is normal and
your carburator air / gas mixture is set properly.

If you see any thing other then that then time for a proper check. Could be
a carburator tune up or leakage, or it could be a leaky cylinder.

I suggest test ya boat again in water and see how it perform with new spark
plug, if problem persist then first thing you should check is open new spark
plugs and look for oil or carbon on the tip if you see any of these sign
that means your spark plugs is or are short. Just simply replacing again
with a new one wont solve the problem. Your boat is looking for a trip to
some workshop.

Regarding capacitor ...there is no harm in replacing it ...... its a cheap
thing and if it is faulty then it could cauz the same symptoms like you
describe in ya first post.

Post by Sixeye
Thanks. I'm not sure what you mean by a "short spark plug". I did
replace all of the plugs today.
One thing I noticed is that the plastic fuel line between the fuel pump
and the carb is attached at either end using tywraps (wow, how high
tech!). The tywrap at the carb end had broken off. I wonder if maybe
that seal was enough to not leak fuel but enough to let air in under load?
I also inspected under the distributor cap and saw that all the contacts
were in pristine condition. I believe there is indeed a capacitor in
there but I wasn't looking for it. And the points seemed to be okay
(without removing them to inspect).
I'm going to pull the boat out of my garage and run it next weekend to
circulate the Stabil I poured in today. Before I run it, I'll check the
bolts to make sure the carb is secured tightly, and look for other
possibilities of air leakage.
What should I be looking for when I inspect the capacitor in the
distributor? Maybe I should just replace it. If I remember right, the
capacitor is to prevent arcing across the points.
--

Post by Awsome
It could be any thing ...
I think you should check your carburator tuning or a leakage of air cauz
at low RPM it works fine with or without load but sputter at high RPM
means could be a air leakage some where in carburator seal.
Second look for some short spark plug, that could be another possibility.
I am not sure if your distributor is equiped with a capacitor usually it
is hidden iside the distributor, check if it is not faulty.

Post by Sixeye
I have an I/O with an OMC 4.3 liter V6. Last time out, about a month
ago, I was losing power any time I got up to about 25 mph or when pulling
a wakeboarder. I could pull the boarder up and get to speed but within
about 30 seconds, the engine would sputter and lose power, completely
stalling if I didn't back off the gas.
While driving with no load (no boarder, that is), I could do fine to
about 23 mph but as soon as I hit 25 or so, the engine would sputter
again.
Does anyone have any suggestions on what I should look for?

[Sixeye]

Thanks. The old plugs had no oil or carbon. They weren't light gray
though, more like a brown.
--

Post by Awsome
May be your engine needs a simple tune up.
Secondly check the old spark plugs if any oil or carbon mark on any one of
them. There color should be light grey on tips if ignition is normal and
your carburator air / gas mixture is set properly.
If you see any thing other then that then time for a proper check. Could
be a carburator tune up or leakage, or it could be a leaky cylinder.
I suggest test ya boat again in water and see how it perform with new
spark plug, if problem persist then first thing you should check is open
new spark plugs and look for oil or carbon on the tip if you see any of
these sign that means your spark plugs is or are short. Just simply
replacing again with a new one wont solve the problem. Your boat is
looking for a trip to some workshop.
Regarding capacitor ...there is no harm in replacing it ...... its a cheap
thing and if it is faulty then it could cauz the same symptoms like you
describe in ya first post.

Post by Sixeye
Thanks. I'm not sure what you mean by a "short spark plug". I did
replace all of the plugs today.
One thing I noticed is that the plastic fuel line between the fuel pump
and the carb is attached at either end using tywraps (wow, how high
tech!). The tywrap at the carb end had broken off. I wonder if maybe
that seal was enough to not leak fuel but enough to let air in under load?
I also inspected under the distributor cap and saw that all the contacts
were in pristine condition. I believe there is indeed a capacitor in
there but I wasn't looking for it. And the points seemed to be okay
(without removing them to inspect).
I'm going to pull the boat out of my garage and run it next weekend to
circulate the Stabil I poured in today. Before I run it, I'll check the
bolts to make sure the carb is secured tightly, and look for other
possibilities of air leakage.
What should I be looking for when I inspect the capacitor in the
distributor? Maybe I should just replace it. If I remember right, the
capacitor is to prevent arcing across the points.
--

Post by Awsome
It could be any thing ...
I think you should check your carburator tuning or a leakage of air cauz
at low RPM it works fine with or without load but sputter at high RPM
means could be a air leakage some where in carburator seal.
Second look for some short spark plug, that could be another
possibility.
I am not sure if your distributor is equiped with a capacitor usually it
is hidden iside the distributor, check if it is not faulty.

Post by Sixeye
I have an I/O with an OMC 4.3 liter V6. Last time out, about a month
ago, I was losing power any time I got up to about 25 mph or when
pulling a wakeboarder. I could pull the boarder up and get to speed but
within about 30 seconds, the engine would sputter and lose power,
completely stalling if I didn't back off the gas.
While driving with no load (no boarder, that is), I could do fine to
about 23 mph but as soon as I hit 25 or so, the engine would sputter
again.
Does anyone have any suggestions on what I should look for?

[Bill Kearney]

Post by Sixeye
One thing I noticed is that the plastic fuel line between the fuel pump and
the carb is attached at either end using tywraps (wow, how high tech!).

The

Post by Sixeye
tywrap at the carb end had broken off. I wonder if maybe that seal was
enough to not leak fuel but enough to let air in under load?

When something stumbles the way you describe it's usually fuel-related.
Most often because not enough fuel is getting into the engine. But just as
much as not enough fuel is a problem, so is too much air.

When checking auto engines it's not uncommon to use propane to find the
leaks. Basically you're letting small amounts of propane out at gasket and
other joining points. If the idle changes (and it would by trying to burn
the propane) then you've found the leak. This is, of course, not something
anyone should be doing unless they know the risks.

Check what the fuel pressure is and make sure it's not dropping when under
load. But also check that the fuel filter is good and that the tank doesn't
have sediment or other gunk being sucked up against the pickup. At idle
gunk in a filter or tank just swirls about. Under high-demand, however, it
gets sucked together and is often enough to stifle the flow.

-Bill Kearney

[avstorm]

Have you checked the fuel filter?
Art

Post by Sixeye
I have an I/O with an OMC 4.3 liter V6. Last time out, about a month ago,
I was losing power any time I got up to about 25 mph or when pulling a
wakeboarder. I could pull the boarder up and get to speed but within about
30 seconds, the engine would sputter and lose power, completely stalling if
I didn't back off the gas.
While driving with no load (no boarder, that is), I could do fine to about
23 mph but as soon as I hit 25 or so, the engine would sputter again.
Does anyone have any suggestions on what I should look for?

[Sixeye]

Yes I have. Thanks. On my boat, the fuel separator is the only fuel filter
there is. It's new this past summer and there is no water or other debris
in it.
--

Post by avstorm
Have you checked the fuel filter?
Art

Post by Sixeye
I have an I/O with an OMC 4.3 liter V6. Last time out, about a month ago,
I was losing power any time I got up to about 25 mph or when pulling a
wakeboarder. I could pull the boarder up and get to speed but within
about 30 seconds, the engine would sputter and lose power, completely
stalling if I didn't back off the gas.
While driving with no load (no boarder, that is), I could do fine to
about 23 mph but as soon as I hit 25 or so, the engine would sputter
again.
Does anyone have any suggestions on what I should look for?

[tango]

check the dwell angle , adjust the points accordingly , then check your
distributor timing , that will do the trick

Post by Sixeye
I have an I/O with an OMC 4.3 liter V6. Last time out, about a month ago,
I was losing power any time I got up to about 25 mph or when pulling a
wakeboarder. I could pull the boarder up and get to speed but within
about 30 seconds, the engine would sputter and lose power, completely
stalling if I didn't back off the gas.
While driving with no load (no boarder, that is), I could do fine to about
23 mph but as soon as I hit 25 or so, the engine would sputter again.
Does anyone have any suggestions on what I should look for?

[Lynn]

Fuel filter fuel filter fuel filter and if that dont fix it check the fuel
filter.

Post by Sixeye
I have an I/O with an OMC 4.3 liter V6. Last time out, about a month ago,
I was losing power any time I got up to about 25 mph or when pulling a
wakeboarder. I could pull the boarder up and get to speed but within about
30 seconds, the engine would sputter and lose power, completely stalling if
I didn't back off the gas.
While driving with no load (no boarder, that is), I could do fine to about
23 mph but as soon as I hit 25 or so, the engine would sputter again.
Does anyone have any suggestions on what I should look for?

[Lynn]

Check at the carburator inlet there will probably be a cartridge filter
behind the big nut the fuel line screw into at the carb.

Post by Sixeye
I have an I/O with an OMC 4.3 liter V6. Last time out, about a month ago,
I was losing power any time I got up to about 25 mph or when pulling a
wakeboarder. I could pull the boarder up and get to speed but within about
30 seconds, the engine would sputter and lose power, completely stalling if
I didn't back off the gas.
While driving with no load (no boarder, that is), I could do fine to about
23 mph but as soon as I hit 25 or so, the engine would sputter again.
Does anyone have any suggestions on what I should look for?