I have a 230hp 305, with a Mercruiser Alpha 1 (1986) and this year when I
run the engine there are a strong smell of gas fumes, the engine is running
rich. It also runs a little rough. Would turning the mixture screw fix
both of these issues? I had the carb rebuilt 2 years ago, and tuned up the
engine the same time. It's not running that rough, and but rougher than
last year. How long do spark plugs and wire last? I also have electronic
ignition if that matters.

Thanks,

Glenn

I should mention there's no performance issues....Just a rough idle and
strong gas smell...


"Glenn Deneweth" wrote in message
...
I have a 230hp 305, with a Mercruiser Alpha 1 (1986) and this year when I
run the engine there are a strong smell of gas fumes, the engine is
running
rich. It also runs a little rough. Would turning the mixture screw fix
both of these issues? I had the carb rebuilt 2 years ago, and tuned up
the
engine the same time. It's not running that rough, and but rougher than
last year. How long do spark plugs and wire last? I also have electronic
ignition if that matters.

Thanks,

Glenn

hi Glenn
If you smell gas fumes then look for gas leak. A leak could be the fuel
tank, or a fuel line, gas tank, or fuel pump. It could be that the screws
that hold the carburetor together have become loose. Try checking tightness
of carburetor screws with screwdriver checking each one (top of carb might
have 6 screws, 4 for accelerator pump on side of carb). Check the fuel
filter if it is an inline filter for loose connection on the hose, if its a
plastic inline filter check for cracks. Inside the carburetor there is a
float bowl vent. If the float bowl overflows then gas can pour out of the
vent and be a hazard. A stuck inlet needle or a pice of dirt between the
inlet needle and the inlet needle seat can cause fuel to overflow. Wires can
last for years. A common test for wires is to examine the wires is by
bending the wire across your finger and looking for cracks in the
insulation, if it shows cracks then replace. If the rubber insulation is
still pliable then they're usually still good. Wires that touch each other
can spark between each other causing engine misfire, poor performance, and
be an ignition source in engine compartments. There are ignition wire
spacers to prevent wires from arching they can be bought at an auto ports
store. Due to the fact that you have electronic ignition the plugs probably
burn clean. Removing the plugs for inspection is usually the only way to see
if they are still good. Plugs can be cleaned and re-used, but on the water
new plugs are most reliable.
If your engine is running rough, and you suspect some fuel connection. The
carburetor's gaskets keep the fuel inside and vacuum from sucking air into
the carburetor. If your carb's gaskets are loose then it is possible your
getting a vacuum leak and poor performance.
I'm not a marine mechanic but have worked on my cars for over 20 years and
rebuilt about 6 carburetors. I had the float bowl over flow problem. Loose
screws on the carb a year later problem where I seemed to smell gas vapors.
After tightening the screws again no vapor smells.
Marine carburetors are different than automobile carburetors.
These are some of the benefits of a marine carb:
Spring loaded needle/seat
Internally vented fuel bowl
Sealed accelerator pump shaft
I don't know that these will prevent you from smelling fuel vapors. But
failure of any fuel system can cause a leak.
If you don't know what to do or the tools or experience then a mechanic can
be worth the money.
If you break down on the water or blow your boat up, a mechanic can save you
more than your money spent.
Greg

"Glenn Deneweth" wrote in message
...
I should mention there's no performance issues....Just a rough idle and
strong gas smell...


"Glenn Deneweth" wrote in message
...
I have a 230hp 305, with a Mercruiser Alpha 1 (1986) and this year when
I
run the engine there are a strong smell of gas fumes, the engine is
running
rich. It also runs a little rough. Would turning the mixture screw fix
both of these issues? I had the carb rebuilt 2 years ago, and tuned up
the
engine the same time. It's not running that rough, and but rougher than
last year. How long do spark plugs and wire last? I also have
electronic
ignition if that matters.

Thanks,

Glenn

Gregory McGuire wrote:
If you smell gas fumes then look for gas leak. A leak could be the fuel
tank, or a fuel line, gas tank, or fuel pump.

I should of been more specific, it's coming from the exhaust. I was also
thinking maybe the choke is sticking?

Wires can
last for years. A common test for wires is to examine the wires is by
bending the wire across your finger and looking for cracks in the
insulation, if it shows cracks then replace. If the rubber insulation is
still pliable then they're usually still good. Wires that touch each other
can spark between each other causing engine misfire, poor performance,
and
be an ignition source in engine compartments. There are ignition wire
spacers to prevent wires from arching they can be bought at an auto ports
store.

Good advice I will inspect the wires tonight.

Due to the fact that you have electronic ignition the plugs probably
burn clean. Removing the plugs for inspection is usually the only way to
see
if they are still good. Plugs can be cleaned and re-used, but on the water
new plugs are most reliable.

I will also inspect a plug tonight...

Thanks,

Glenn

glenn
Could it be a stuck choke - sitting for so long? take off air cleaner -
spray with choke cleaner / carburetor cleaner....you can clean the linkage
with it too. Test your results. Is the engine cold with rough idle or
hot/operating temperature?
greg
p.s.
I have been trying to find other articles on internet with same problem. You
could be running too rich, finding out why is that hard part to figure out.
"Glenn Deneweth" wrote in message
...

Gregory McGuire wrote:
If you smell gas fumes then look for gas leak. A leak could be the fuel
tank, or a fuel line, gas tank, or fuel pump.

I should of been more specific, it's coming from the exhaust. I was also
thinking maybe the choke is sticking?

Wires can
last for years. A common test for wires is to examine the wires is by
bending the wire across your finger and looking for cracks in the
insulation, if it shows cracks then replace. If the rubber insulation is
still pliable then they're usually still good. Wires that touch each
other
can spark between each other causing engine misfire, poor performance,
and
be an ignition source in engine compartments. There are ignition wire
spacers to prevent wires from arching they can be bought at an auto
ports
store.

Good advice I will inspect the wires tonight.

Due to the fact that you have electronic ignition the plugs probably
burn clean. Removing the plugs for inspection is usually the only way to
see
if they are still good. Plugs can be cleaned and re-used, but on the
water
new plugs are most reliable.

I will also inspect a plug tonight...

Thanks,

Glenn

Gregory McGuire writes...
Could it be a stuck choke - sitting for so long? take off air cleaner -
spray with choke cleaner / carburetor cleaner....you can clean the linkage
with it too. Test your results. Is the engine cold with rough idle or
hot/operating temperature?

The engine is cold when I notice the rough idling....

A misfire causes gas smell in a hurry. Replace your plugs, plug wires,
distributor cap & rotor. These are fairly cheap and easy to replace. I
would then go to after the carb.

"Glenn Deneweth" wrote in message
...
I should mention there's no performance issues....Just a rough idle and
strong gas smell...


"Glenn Deneweth" wrote in message
...
I have a 230hp 305, with a Mercruiser Alpha 1 (1986) and this year when
I
run the engine there are a strong smell of gas fumes, the engine is
running
rich. It also runs a little rough. Would turning the mixture screw fix
both of these issues? I had the carb rebuilt 2 years ago, and tuned up
the
engine the same time. It's not running that rough, and but rougher than
last year. How long do spark plugs and wire last? I also have
electronic
ignition if that matters.

Thanks,

Glenn

"Glenn Deneweth" wrote in message
...
I have a 230hp 305, with a Mercruiser Alpha 1 (1986) and this year when I
run the engine there are a strong smell of gas fumes, the engine is
running
rich. It also runs a little rough. Would turning the mixture screw fix
both of these issues?

The screws only adjust the idle mixture. If you get the symptoms at
anything above idle then this won't help.

How do you know the engine is running rich?

A strong smell of gas is bad, so you should solve that problem ASAP.

Rod

Rod McInnis wrote:
The screws only adjust the idle mixture. If you get the symptoms at
anything above idle then this won't help.

How do you know the engine is running rich?

When running at idle, the smell of gas is strong from the exhaust, there is
no smell inside the boat, it's only from when the boat is running, I noticed
a couple other boats on my finger doing the same thing.

"Glenn Deneweth" wrote in message
news
When running at idle, the smell of gas is strong from the exhaust, there
is
no smell inside the boat, it's only from when the boat is running, I
noticed
a couple other boats on my finger doing the same thing.


If this is just a cold start issue then I wouldn't worry too much about it.
If this continues after the engine has warmed up then I would suspect the
choke.

If the choke doesn't back off then perhaps the choke heater isn't working.
A common arrangment is to have an electric heating element next to the
bi-metal spring that operates the choke. When the ignition is turned on,
the electric current heats the spring and slowly opens the choke. If the
wires aren't hooked up, or if the heating element is broken (common failure)
then the choke will never open.

In most cases, the amount of choke applied is easily adjusted. The choke
housing is usually secured by three clips around the outside. If you loosen
the screws you can rotate the housing. Rotating one way will increase the
amount of choke, rotate the other to decrease.

For sure, when the engine is fully warmed up the choke should be fully off.
Unless it is really cold I would not expect the choke to be fully engage.
If you take the spark arrester off the top of the carburetor you should be
able to see the choke valve and establish if it is fully open or not.

Rod