Mariner 4HP Cutting out - Fuel tank location
 

My first post here .. I launched my boat today after the long danish
winter, to experience problems with my four-stroke 4HP Mariner
Outboard. The motor started fine (only 4 - 5 attempts) For some reason
or other the motor cuts out after a few minutes, and I have a feeling
that there is something up with the fuel supply. I have an external
fuel tank which is positioned below the motor's fuel inlet, so the
fuel hose has to travel up before being lead through the transom and
into the motor .... could this possible cause the problem, i.e. a fuel
syphon problem, is there a maximum fuel hose length (mine is probably
about 2m long? The motor will start again after 30 seconds or so after
I have pumped more fuel to the motor and given it some choke. Any help
appreciated.

Mariner 4HP Cutting out - Fuel tank location
 

"il_papa" wrote in message
oups.com...
My first post here .. I launched my boat today after the long danish
winter, to experience problems with my four-stroke 4HP Mariner
Outboard. The motor started fine (only 4 - 5 attempts) For some reason
or other the motor cuts out after a few minutes, and I have a feeling
that there is something up with the fuel supply. I have an external
fuel tank which is positioned below the motor's fuel inlet, so the
fuel hose has to travel up before being lead through the transom and
into the motor .... could this possible cause the problem, i.e. a fuel
syphon problem, is there a maximum fuel hose length (mine is probably
about 2m long? The motor will start again after 30 seconds or so after
I have pumped more fuel to the motor and given it some choke. Any help
appreciated.


Check the vent on the remote tank. Oftentimes after a storage episode
the rubber grommet in the vent in the fuel tank cap becomes squashed and
collapsed so even if it's in the open position it fails to allow air
into the tank and a vacuum develops. Try running the engine with the
fuel fill cap loose at the threads to see if the problem stops. If so
troubleshoot the vent mechanism or purchase a new cap.

Wilbur Hubbard

Mariner 4HP Cutting out - Fuel tank location
 

On 2007-04-15 15:19:00 -0400, "Wilbur Hubbard"
said:

"il_papa" wrote in message
oups.com...
My first post here .. I launched my boat today after the long danish
winter, to experience problems with my four-stroke 4HP Mariner
Outboard. The motor started fine (only 4 - 5 attempts) For some reason
or other the motor cuts out after a few minutes, and I have a feeling
that there is something up with the fuel supply. I have an external
fuel tank which is positioned below the motor's fuel inlet, so the
fuel hose has to travel up before being lead through the transom and
into the motor .... could this possible cause the problem, i.e. a fuel
syphon problem, is there a maximum fuel hose length (mine is probably
about 2m long? The motor will start again after 30 seconds or so after
I have pumped more fuel to the motor and given it some choke. Any help
appreciated.


Check the vent on the remote tank. Oftentimes after a storage episode
the rubber grommet in the vent in the fuel tank cap becomes squashed
and collapsed so even if it's in the open position it fails to allow
air into the tank and a vacuum develops. Try running the engine with
the fuel fill cap loose at the threads to see if the problem stops. If
so troubleshoot the vent mechanism or purchase a new cap.

Wilbur Hubbard

Agreement. That's the most usual suspect of that sort of behavior. Pump
the priming bulb and see if it's still "hard". (If not, look for a bad
connection in the hose.) After that, I'd check the bowl & float for
gunk, possibly rebuild the carb if you have any doubts.

Another thing that sometimes causes intermittent problems is the kill
switch. You might also have a switch at the fuel connector. Sometimes
vibrations will cause either to turn the engine off. Pull the plug and
lay it on the head to see if you're getting spark. At the same time,
you might smell/see if you're getting fuel.

--
Jere Lull
Tanzer 28 #4 out of Tolchester, MD
Xan's new pages: http://web.mac.com/jerelull/iWeb/Xan/
Our BVI pages: http://homepage.mac.com/jerelull/BVI/

Mariner 4HP Cutting out - Fuel tank location
 

Thanks for the advice ... the fuel tank cap vent sounds like a
distinct possibility, so I'll check that out. I should possibly
explain what is happening a bit more accurately. The motor's rev level
becomes unsteady and becomes a mixture of slowing and or misfiring,
and then cuts out. Its not like it happens all of a sudden, and I can
tell when it is going to cut out, but I don't seem to be able to stop
it happening ... seems to happen at the worst possible times too...

Mariner 4HP Cutting out - Fuel tank location
 

If you can keep it running by pumping the primer ball or if it will
run if you keep a lot of choke on it you might have a partial blockage
in the carb. You could try draining the bowl and spraying some
varnish remover into the inlet, but it is better to strip the thing
down and fire cleaner through all the little passages. That isn't
hard. While you have it off take the fuel pump off and check that it
hasn't gotten clogged, that the diaphragm has no holes and that the
spring is still good.

-- Tom.

Mariner 4HP Cutting out - Fuel tank location
 

"il_papa" wrote in news:1176661659.793213.280450
@n59g2000hsh.googlegroups.com:

My first post here .. I launched my boat today after the long danish
winter, to experience problems with my four-stroke 4HP Mariner
Outboard. The motor started fine (only 4 - 5 attempts) For some reason
or other the motor cuts out after a few minutes, and I have a feeling
that there is something up with the fuel supply. I have an external
fuel tank which is positioned below the motor's fuel inlet, so the
fuel hose has to travel up before being lead through the transom and
into the motor .... could this possible cause the problem, i.e. a fuel
syphon problem, is there a maximum fuel hose length (mine is probably
about 2m long? The motor will start again after 30 seconds or so after
I have pumped more fuel to the motor and given it some choke. Any help
appreciated.



That pumping bulb is the finest troubleshooting equipment an outboard
motor ever had.....

When you pump it up, does it ever get hard and refuse to pump any more or
does it just keep pumping until gas starts running out of the motor?

If it starts running out, does it run out the case or the exhaust or
both?

What it SHOULD do is to pump until the float valve closes then refuse to
pump any more getting "hard" as you can't compress the liquid. Call that
"normal". Two possible problems raise their ugly heads if it doesn't....

1) The pulse fuel pump diaphram is ripped, rendering it useless.
Continued pumping of the bulb, in a 4-stroker, floods the crankcase with
gas, thinning the lube oil into oblivion and causing the motor to go
unlubricated until the bearings wear out or seize, completely. 2-
strokers, much better engines to fix, merely flood one crankcase chamber
through the pulse tube, which clears....well, unless the stupid motor is
oil injected and there's no lube oil in the gas to lube the bearings you
just washed down with raw gas. Premixed gas/oil 2-stroker? No problemo!

If the diaphram is ripped, the pump won't pump gas uphill from the
tank...fuel starvation ensues. Crank the engine and when it starts to
stall, pump the bulb and see if it takes off again. If it will run with
you slowly pumping the bulb, the fuel pump diaphram is ripped, replace
it. If the bulb collapses when the engine is running, something is
clogging the fuel flow BELOW the bulb, back towards the tank. Watch the
bulb as the engine runs to see if it slowly collapses. That would
indicate a good fuel pump making the vacuum, but no gas flowing up into
the bulb as the vacuum increases into fuel starvation.

2) The float valve in the carb is stuck open, flooding the engine with
gas as the level is way too high or is dumping raw gas down its intake.
This happens when Joe Boater stores the engine WITHOUT running the gas
out of the float bowl. The light elements evaporate out the various
ports in the bowl, while what's left turns to that gummy brown shellac,
clogging up the jets and making the valve stick. Always run the engine
dry by unplugging the tank and leaving it run until it stumbles, then
full choke before it stalls to suck out any gas that's left by the choke
pulling a vacuum on the holes to the jets. Never store a motor with gas
in the carb(s).

Let us know how we did! I found a boater stranded, motor cover off,
staring into the beast (V-6 Merc 150). "Have you pumped the bulb since
it died?", I asked gingerly as he was bigger than me by a bit. Of course
not, he took the cover off and was staring into its guts without
thinking. After he cleaned off some of the major pluff mud he was knee
deep in behind the motor, I told him to pump the bulb up hard. He looked
at the bulb and it was FLAT!...sucked FLAT by the fuel pump. "Open the
fuel tank valve and let's see if that fixes it." (I tried not to show any
mirth or just belly laugh at that point.) He opened the valve, the bulb
popped back out. "Now pump it up hard for me, just for old times sake."
He was quite cooperative, at that point, having saved him from being
towed for 10 miles to the trailer. Mr Merc roared to life and ran like
new. He and his wife went on their way after a short raft up to have a
complementary beer from the big white cooler....(c; I love that bulb...



Larry
--

Mariner 4HP Cutting out - Fuel tank location
 

In article ,
Larry wrote:
fuel tank valve and let's see if that fixes it." (I tried not to show any
mirth or just belly laugh at that point.) He opened the valve, the bulb
popped back out. "Now pump it up hard for me, just for old times sake."
He was quite cooperative, at that point, having saved him from being
towed for 10 miles to the trailer. Mr Merc roared to life and ran like
new. He and his wife went on their way after a short raft up to have a
complementary beer from the big white cooler....(c; I love that bulb...

And then, just to thank you, he kicked the crap out of you? g

--
Capt. JG @@
www.sailnow.com

Mariner 4HP Cutting out - Fuel tank location
 

Mariner 4HP Cutting out - Fuel tank location
 

Thanks for the advice guys ... the motor is running much better ....
once I dealt with the fuel tank vent

Mariner 4HP Cutting out - Fuel tank location
 

"il_papa" wrote in message
oups.com...
Thanks for the advice guys ... the motor is running much better ....
once I dealt with the fuel tank vent


You're welcome.

Wilbur Hubbard - master mariner and master mechanic.