I have a lawn mower (which I found on the curb) that runs OK for a few
minutes sometimes longer, but inevitably stalls, needs to be re-
primed, and re-started. (But will restart with no wait.) When it dies,
and I go to re-prime it, you can hear and feel that the primer bulb
sucking air at first, turning to a more reasonable fuel sucking sound/
feel at times (or after a few tries).

When I got it I replaced the spark plug, changed out the oil twice,
cleaned out the carb, replaced the fuel line, replaced the needle
valve and a badly deteriorated seat, and put the thing back together.
There seemed to have been some water in the engine, as the first
change of oil was very cloudy. It is a 4.5 hp Briggs and Stratton
12H800, in a Murray 204210X8B.

Not sure where the primer is pulling air from, why it is stalling, or
how to fix the issue (cheaply). Any suggestions would be greatly
appreciated.

Thanks.

Jerry

check the air equalisation hole in the fuel cap and
the float valve
wrote in message
ups.com...
I have a lawn mower (which I found on the curb) that runs OK for a few
minutes sometimes longer, but inevitably stalls, needs to be re-
primed, and re-started. (But will restart with no wait.) When it dies,
and I go to re-prime it, you can hear and feel that the primer bulb
sucking air at first, turning to a more reasonable fuel sucking sound/
feel at times (or after a few tries).

When I got it I replaced the spark plug, changed out the oil twice,
cleaned out the carb, replaced the fuel line, replaced the needle
valve and a badly deteriorated seat, and put the thing back together.
There seemed to have been some water in the engine, as the first
change of oil was very cloudy. It is a 4.5 hp Briggs and Stratton
12H800, in a Murray 204210X8B.

Not sure where the primer is pulling air from, why it is stalling, or
how to fix the issue (cheaply). Any suggestions would be greatly
appreciated.

Thanks.

Jerry

wrote in message
ups.com...
I have a lawn mower (which I found on the curb) that runs OK for a few
minutes sometimes longer, but inevitably stalls, needs to be re-
primed, and re-started. (But will restart with no wait.) When it dies,
and I go to re-prime it, you can hear and feel that the primer bulb
sucking air at first, turning to a more reasonable fuel sucking sound/
feel at times (or after a few tries).

When I got it I replaced the spark plug, changed out the oil twice,
cleaned out the carb, replaced the fuel line, replaced the needle
valve and a badly deteriorated seat, and put the thing back together.
There seemed to have been some water in the engine, as the first
change of oil was very cloudy. It is a 4.5 hp Briggs and Stratton
12H800, in a Murray 204210X8B.

Not sure where the primer is pulling air from, why it is stalling, or
how to fix the issue (cheaply). Any suggestions would be greatly
appreciated.


Lossen the gas cap a couple turns, and see if the problem goes away. If so, the
vent on the gas cap is not working right.

Bob

on 9/3/2007 10:12 PM said the following:
I have a lawn mower (which I found on the curb) that runs OK for a few
minutes sometimes longer, but inevitably stalls, needs to be re-
primed, and re-started. (But will restart with no wait.) When it dies,
and I go to re-prime it, you can hear and feel that the primer bulb
sucking air at first, turning to a more reasonable fuel sucking sound/
feel at times (or after a few tries).

When I got it I replaced the spark plug, changed out the oil twice,
cleaned out the carb, replaced the fuel line, replaced the needle
valve and a badly deteriorated seat, and put the thing back together.
There seemed to have been some water in the engine, as the first
change of oil was very cloudy. It is a 4.5 hp Briggs and Stratton
12H800, in a Murray 204210X8B.

Not sure where the primer is pulling air from, why it is stalling, or
how to fix the issue (cheaply). Any suggestions would be greatly
appreciated.

Thanks.

Jerry


Besides what others have said, check the pickup tube in the bottom of
the fuel tank for debris (some have a small screen on the pickup).
Pull the hose off the tank and see if the gas flows freely out of the
tank. If it does, put it back on and then pull the fuel line off the
carburetor and see if the gas flows freely from that end of the tube. If
not, the problem lies in the fuel line or gas tank. Otherwise it's the
carburetor.
I have blown into the fuel line at the carburetor end and listened for
bubbling in the tank.

--

Bill
In Hamptonburgh, NY
To email, remove the double zeroes after @

All good suggestions, but sadly all were tried and failed to reveal
the problem. Gas flows freely through the new gas line; it still
stalls, even running with the gas cap off (seemed like despite all the
other gunk on it, the fuel tank was clean); I have blown out the carb
with cleaner, and all the tiny holes seem to be free of debris (the
ones I could find, that is).

My next step would probably be to replace all the gaskets in the carb
-- assuming that one of them is leaking air and causing the engine to
lose prime. Not sure if that is even remotely resonable though.
Thoughts?

Thanks for everything so far. I wasn't sure (in Telstra's response)
what/where the float valve is, but I am happy to check it ...

On 9/5/2007 8:02 AM, wrote:
All good suggestions, but sadly all were tried and failed to reveal
the problem. Gas flows freely through the new gas line; it still
stalls, even running with the gas cap off (seemed like despite all the
other gunk on it, the fuel tank was clean); I have blown out the carb
with cleaner, and all the tiny holes seem to be free of debris (the
ones I could find, that is).

My next step would probably be to replace all the gaskets in the carb
-- assuming that one of them is leaking air and causing the engine to
lose prime. Not sure if that is even remotely resonable though.
Thoughts?

Thanks for everything so far. I wasn't sure (in Telstra's response)
what/where the float valve is, but I am happy to check it ...

Have you replaced the primer bulb/fuel lines? The kit usually has both
the bulb and lines. About $7 @ Lowes.

--
Ted
I wasn't born in Texas but
I got back here as soon as I could


If you never try anything new, you'll miss out on many of life's great
disappointments.

On Wed, 05 Sep 2007 13:02:06 -0000, wrote:

All good suggestions, but sadly all were tried and failed to reveal
the problem. Gas flows freely through the new gas line; it still
stalls, even running with the gas cap off (seemed like despite all the
other gunk on it, the fuel tank was clean); I have blown out the carb
with cleaner, and all the tiny holes seem to be free of debris (the
ones I could find, that is).

Some "tiny holes" need to be cleaned with a piece of wire. A wire
plucked from a wire brush (stainless is best). These ports clog and
you don't get the right air/fuel mixture in the carb throat.


My next step would probably be to replace all the gaskets in the carb
-- assuming that one of them is leaking air and causing the engine to
lose prime. Not sure if that is even remotely resonable though.
Thoughts?

Thanks for everything so far. I wasn't sure (in Telstra's response)
what/where the float valve is, but I am happy to check it ...

Have you tried to run this engine without an air filter after it
stalls? Pull the air filter off, run it and see if it stalls.

Before it dies out, can you spray carb fluid in to keep it running?

--
Oren

"The voices in my head may not be real, but they have some good ideas!"

On Thu, 06 Sep 2007 15:24:08 -0700, Oren wrote:

On Wed, 05 Sep 2007 13:02:06 -0000, wrote:

All good suggestions, but sadly all were tried and failed to reveal
the problem. Gas flows freely through the new gas line; it still
stalls, even running with the gas cap off (seemed like despite all the
other gunk on it, the fuel tank was clean); I have blown out the carb
with cleaner, and all the tiny holes seem to be free of debris (the
ones I could find, that is).

Some "tiny holes" need to be cleaned with a piece of wire. A wire
plucked from a wire brush (stainless is best). These ports clog and
you don't get the right air/fuel mixture in the carb throat.


My next step would probably be to replace all the gaskets in the carb
-- assuming that one of them is leaking air and causing the engine to
lose prime. Not sure if that is even remotely resonable though.
Thoughts?

Thanks for everything so far. I wasn't sure (in Telstra's response)
what/where the float valve is, but I am happy to check it ...

Have you tried to run this engine without an air filter after it
stalls? Pull the air filter off, run it and see if it stalls.

Before it dies out, can you spray carb fluid in to keep it running?

Muffler may be clogged. Engine needs to breath just like a human,
inhale and EXHALE! Check your muffler for free air flow.

Cheers,
Joe

On Thu, 06 Sep 2007 17:38:28 -0500, Joe wrote:

On Thu, 06 Sep 2007 15:24:08 -0700, Oren wrote:

On Wed, 05 Sep 2007 13:02:06 -0000, wrote:

All good suggestions, but sadly all were tried and failed to reveal
the problem. Gas flows freely through the new gas line; it still
stalls, even running with the gas cap off (seemed like despite all the
other gunk on it, the fuel tank was clean); I have blown out the carb
with cleaner, and all the tiny holes seem to be free of debris (the
ones I could find, that is).

Some "tiny holes" need to be cleaned with a piece of wire. A wire
plucked from a wire brush (stainless is best). These ports clog and
you don't get the right air/fuel mixture in the carb throat.


My next step would probably be to replace all the gaskets in the carb
-- assuming that one of them is leaking air and causing the engine to
lose prime. Not sure if that is even remotely resonable though.
Thoughts?

Thanks for everything so far. I wasn't sure (in Telstra's response)
what/where the float valve is, but I am happy to check it ...

Have you tried to run this engine without an air filter after it
stalls? Pull the air filter off, run it and see if it stalls.

Before it dies out, can you spray carb fluid in to keep it running?

Muffler may be clogged. Engine needs to breath just like a human,
inhale and EXHALE! Check your muffler for free air flow.


I've heard of this, but never had it happen too me.

Maybe an air/fuel mixture screw adjustment would help the OP.

--
Oren

"The voices in my head may not be real, but they have some good ideas!"