Hi., I just bought a brand new petrol mower this weekend. I measured
and filled the oil and petrol correctly. Its a 4 stroke engine

It starts without too much difficulty (though not as easy as Id
expected).
After mowing for maybe 30 seconds, the motor rapidly fades and then
stops.
At this point the starting cord is very tough to pull, and I generally
have to leave it for a while before I can start it as easily as before.

Im not sure what Im doing wrong or why its cutting out. Someone
suggested Id put in too much oil, but I followed the instructions and
dont see any smoke indicative of oil burning off

Its my first petrol mower so Im a bit unsure what else could be wrong.
Any advice appreciated

Cheers
Carpii

On 20 Jun 2006 05:02:42 -0700, "Carpii" wrote:

Hi., I just bought a brand new petrol mower this weekend. I measured
and filled the oil and petrol correctly. Its a 4 stroke engine

It starts without too much difficulty (though not as easy as Id
expected).
After mowing for maybe 30 seconds, the motor rapidly fades and then
stops.
At this point the starting cord is very tough to pull, and I generally
have to leave it for a while before I can start it as easily as before.

Im not sure what Im doing wrong or why its cutting out. Someone
suggested Id put in too much oil, but I followed the instructions and
dont see any smoke indicative of oil burning off

Its my first petrol mower so Im a bit unsure what else could be wrong.
Any advice appreciated

Cheers
Carpii

Sounds like the choke isn't working and it's flooding itself.

Carpii wrote:
Hi., I just bought a brand new petrol mower this weekend. I measured
and filled the oil and petrol correctly. Its a 4 stroke engine

It starts without too much difficulty (though not as easy as Id
expected).
After mowing for maybe 30 seconds, the motor rapidly fades and then
stops.
At this point the starting cord is very tough to pull, and I generally
have to leave it for a while before I can start it as easily as
before.

Im not sure what Im doing wrong or why its cutting out. Someone
suggested Id put in too much oil, but I followed the instructions and
dont see any smoke indicative of oil burning off

Its my first petrol mower so Im a bit unsure what else could be wrong.
Any advice appreciated

Cheers
Carpii

you /have/ switched the fuel tap on, haven't you ?

"Carpii" wrote in message
oups.com...
Hi., I just bought a brand new petrol mower this weekend. I measured
and filled the oil and petrol correctly. Its a 4 stroke engine

It starts without too much difficulty (though not as easy as Id
expected).
After mowing for maybe 30 seconds, the motor rapidly fades and then
stops.
At this point the starting cord is very tough to pull, and I generally
have to leave it for a while before I can start it as easily as before.

If the engine is getting tight as you describe it indicates it is seizing
due to lack of oil. How you square this with having filled the oil correctly
I don't know but, if it were a fuel problem as others have suggested, the
engine would not be tight. Without looking at it it is difficult to help but
I would siggest, at least, getting a second opinion on the oil filling.


--
Bob Mannix
(anti-spam is as easy as 1-2-3 - not)

Carpii wrote:
Hi., I just bought a brand new petrol mower this weekend. I measured
and filled the oil and petrol correctly. Its a 4 stroke engine

It starts without too much difficulty (though not as easy as Id
expected).
After mowing for maybe 30 seconds, the motor rapidly fades and then
stops.

That sounds like a blockage in the fuel system somewhere...


At this point the starting cord is very tough to pull, and I generally
have to leave it for a while before I can start it as easily as before.

That does not.


Im not sure what Im doing wrong or why its cutting out. Someone
suggested Id put in too much oil, but I followed the instructions and
dont see any smoke indicative of oil burning off

It's likely to smoke a lot if it's too full. Check that there
is enough oil, and you've put it in the correct hole. There
should be a way of checking the level, see the handbook (what
sort of mower is it AAMOI?).


Its my first petrol mower so Im a bit unsure what else could be wrong.
Any advice appreciated

If it's got the right amount of the correct oil in it then it
sounds like a fault (no ring clearance?), and it might be
best to take it back!

However, look in the book!

"Carpii" wrote in message
oups.com...
Hi., I just bought a brand new petrol mower this weekend. I measured
and filled the oil and petrol correctly. Its a 4 stroke engine

It starts without too much difficulty (though not as easy as Id
expected).
After mowing for maybe 30 seconds, the motor rapidly fades and then
stops.
At this point the starting cord is very tough to pull, and I generally
have to leave it for a while before I can start it as easily as before.

Im not sure what Im doing wrong or why its cutting out. Someone
suggested Id put in too much oil, but I followed the instructions and
dont see any smoke indicative of oil burning off

Its my first petrol mower so Im a bit unsure what else could be wrong.
Any advice appreciated


Daft assumption I know, but you ARE keeping hold of the 'Dead Mans Handle'
aren't you?

HTH

John

On 20 Jun 2006 05:02:42 -0700, Carpii wrote:

It starts without too much difficulty (though not as easy as Id
expected). After mowing for maybe 30 seconds, the motor rapidly fades
and then stops.

At this point the starting cord is very tough to pull, and I generally
have to leave it for a while before I can start it as easily as before.

As others have said check the oil and fuel levels. There probably isn't a
choke or fuel valve but that depends on the engine and mower.

Another possibilty is that the brake that quickly stops the engine
rotating when you release the dead mans handle isn't releasing properly
and after a while heats up and binds on hard enough to stall the engine.

You are operating the deadmans handle when starting? I think you must be
as the engine runs and they normally short the magneto out as well
killing the spark. Check that the brake is coming off properly.

--
Cheers
Dave. pam is missing e-mail

Carpii wrote:
Hi., I just bought a brand new petrol mower this weekend. I measured
and filled the oil and petrol correctly. Its a 4 stroke engine

It starts without too much difficulty (though not as easy as Id
expected).
After mowing for maybe 30 seconds, the motor rapidly fades and then
stops.


At this point the starting cord is very tough to pull, and I generally
have to leave it for a while before I can start it as easily as
before.


Thats true as their will be pressure still in the piston chamber and
leaving it a while,the pressure is gradually diminishing.

Im not sure what Im doing wrong or why its cutting out. Someone
suggested Id put in too much oil, but I followed the instructions and
dont see any smoke indicative of oil burning off


Are keeping your fingers on the throttle evenly as your cutting?

Its my first petrol mower so Im a bit unsure what else could be wrong.
Any advice appreciated

Cheers
Carpii

If in doubt take it back.

--
Sir Benjamin Middlethwaite

Bob Mannix wrote:
"Carpii" wrote in message
oups.com...
Hi., I just bought a brand new petrol mower this weekend. I measured
and filled the oil and petrol correctly. Its a 4 stroke engine

It starts without too much difficulty (though not as easy as Id
expected).
After mowing for maybe 30 seconds, the motor rapidly fades and then
stops.
At this point the starting cord is very tough to pull, and I
generally have to leave it for a while before I can start it as
easily as before.

If the engine is getting tight as you describe it indicates it is
seizing due to lack of oil. How you square this with having filled
the oil correctly I don't know but, if it were a fuel problem as
others have suggested, the engine would not be tight. Without looking
at it it is difficult to help but I would siggest, at least, getting
a second opinion on the oil filling.

Nothing to do with pressure in the chamber then?
It being brand new an all. ;-)

--
Sir Benjamin Middlethwaite

On Tue, 20 Jun 2006 12:02:42 UTC, "Carpii" wrote:

Hi., I just bought a brand new petrol mower this weekend. I measured
and filled the oil and petrol correctly. Its a 4 stroke engine

It starts without too much difficulty (though not as easy as Id
expected).
After mowing for maybe 30 seconds, the motor rapidly fades and then
stops.
At this point the starting cord is very tough to pull, and I generally
have to leave it for a while before I can start it as easily as before.

Blocked vent on the fuel tank (in the filler cap)?

--
The information contained in this post is copyright the
poster, and specifically may not be published in, or used by
Avenue Supplies, http://avenuesupplies.co.uk

"The3rd Earl Of Derby" wrote in message
. uk...
Bob Mannix wrote:
"Carpii" wrote in message
oups.com...
Hi., I just bought a brand new petrol mower this weekend. I measured
and filled the oil and petrol correctly. Its a 4 stroke engine

It starts without too much difficulty (though not as easy as Id
expected).
After mowing for maybe 30 seconds, the motor rapidly fades and then
stops.
At this point the starting cord is very tough to pull, and I
generally have to leave it for a while before I can start it as
easily as before.

If the engine is getting tight as you describe it indicates it is
seizing due to lack of oil. How you square this with having filled
the oil correctly I don't know but, if it were a fuel problem as
others have suggested, the engine would not be tight. Without looking
at it it is difficult to help but I would siggest, at least, getting
a second opinion on the oil filling.

Nothing to do with pressure in the chamber then?
It being brand new an all. ;-)

He said "very tough to pull" so I would say not (as you ask ). The pressure
will release as soon as a valve opens, which will be after a small fraction
of a revolution, after which there will be no pressure - unitl - the main
pressure is built up during the compression stroke (obviously, the clue is
in the name) which will be the same whether it has just been running or has
been left for a while. A new mower will have higher compression than an old
one but it won't change from minute to minute.


--
Bob Mannix
(anti-spam is as easy as 1-2-3 - not)

The3rd Earl Of Derby wrote:
Carpii wrote:
Hi., I just bought a brand new petrol mower this weekend. I measured
and filled the oil and petrol correctly. Its a 4 stroke engine

It starts without too much difficulty (though not as easy as Id
expected).
After mowing for maybe 30 seconds, the motor rapidly fades and then
stops.


At this point the starting cord is very tough to pull, and I
generally have to leave it for a while before I can start it as
easily as before.


Thats true as their will be pressure still in the piston chamber and
leaving it a while,the pressure is gradually diminishing.


There will only be pressure in the cylinder if it stops at, or approaching,
tdc on the compression stroke. Which it wouldn't. Ever. It should not be any
harder to start whether it's been running or not, in fact it will start
easier if it's warm for obvious reasons.

It's either partially seizing due to lack of oil, which seems unlikely as it
would probably keep running until it did seize properly, or the dead man's
handle is binding somehow when it's warm.

OP: Take it back to the shop.

Si

Chris Bacon wrote:
Carpii wrote:
Hi., I just bought a brand new petrol mower this weekend. I measured
and filled the oil and petrol correctly. Its a 4 stroke engine

That sounds like a blockage in the fuel system somewhere...

Too true, sounds like it is seizing. If you are using two stroke in a
four stroke engine, it will choke up until the oil drains out. It will
eventually soot up the plug.

There is a minor chance of it clonking due to a weak mixture as the
unburned oil counts as petrol starvation. It's only an interesting
accademic point for model airplane engines though.
:
What mix of oil and petrol are you using, Carpii?

The tank valve is probably blocked. You will find it runs for a little
longer on a near empty tank than on a full one if that is so but just
clean the vent rather than miss around with it. Also, check the air
filter is clean.

As long as there is some oil in the crank case there is no problem with
the oil situation. If you take the plug out its colour will tell you if
the mixture is too oily, too rich or whatever. If it's not that then it
might be te timing. This will "go out" if you mow a brick or something.

I wouldn't mess around with anything technical, just take it back if
it's not the vent or air filter.

Bob Eager wrote:
.

Blocked vent on the fuel tank (in the filler cap)?


Happened on my mower. Missus had a go while I was in hospital. Put the
cap off the petrol can on top of the mower & vice versa. Ran until it
pulled a vacuum and then cut out.

Weatherlawyer wrote:
Chris Bacon wrote:
Carpii wrote:
Hi., I just bought a brand new petrol mower this weekend. I measured
and filled the oil and petrol correctly. Its a 4 stroke engine

That sounds like a blockage in the fuel system somewhere...

Too true, sounds like it is seizing. If you are using two stroke in a
four stroke engine, it will choke up until the oil drains out. It will
eventually soot up the plug.

There is a minor chance of it clonking due to a weak mixture as the
unburned oil counts as petrol starvation. It's only an interesting
accademic point for model airplane engines though.
:
What mix of oil and petrol are you using, Carpii?


He SAID its a 4-stroke...

The tank valve is probably blocked. You will find it runs for a little
longer on a near empty tank than on a full one if that is so but just
clean the vent rather than miss around with it. Also, check the air
filter is clean.

As long as there is some oil in the crank case there is no problem with
the oil situation. If you take the plug out its colour will tell you if
the mixture is too oily, too rich or whatever. If it's not that then it
might be te timing. This will "go out" if you mow a brick or something.

I wouldn't mess around with anything technical, just take it back if
it's not the vent or air filter.


It could be many many things.

My guess would be he hasn't released the choke. Or has released it too soon.

If its full of ordinary engine oil, which it should be, its not gonna seize.

These things are only splash lubricated y'know. No oil pump etc etc.

On Tue, 20 Jun 2006 19:07:18 +0100, The Natural Philosopher wrote:

What mix of oil and petrol are you using, Carpii?

He SAID its a 4-stroke...

Ah but does he know that you don't (generally) put the oil in the petrol
with a 4 stroke...

My guess would be he hasn't released the choke. Or has released it too
soon.

My mower doesn't have a choke as such just a primer bulb which you push a
few times. This squirts extra fuel into the carb to get it going from
cold. These little air cooled engines need very little choke even if
manually operated.

--
Cheers
Dave. pam is missing e-mail

Carpii wrote in message
oups.com...
Hi., I just bought a brand new petrol mower this weekend. I measured
and filled the oil and petrol correctly. Its a 4 stroke engine

It starts without too much difficulty (though not as easy as Id
expected).
After mowing for maybe 30 seconds, the motor rapidly fades and then
stops.
At this point the starting cord is very tough to pull, and I generally
have to leave it for a while before I can start it as easily as before.


What make of mower is it, ive heard that the Chinese manufactured engine in
the Challenge/Power devil type mower is extremely unreliable.

You did put the oil in the crankcase and not mixed with the petrol ?



-

"Carpii" wrote in message
oups.com...
Hi., I just bought a brand new petrol mower this weekend. I measured
and filled the oil and petrol correctly. Its a 4 stroke engine

It starts without too much difficulty (though not as easy as Id
expected).
After mowing for maybe 30 seconds, the motor rapidly fades and then
stops.
At this point the starting cord is very tough to pull, and I generally
have to leave it for a while before I can start it as easily as before.

Im not sure what Im doing wrong or why its cutting out. Someone
suggested Id put in too much oil, but I followed the instructions and
dont see any smoke indicative of oil burning off

Its my first petrol mower so Im a bit unsure what else could be wrong.
Any advice appreciated

Cheers
Carpii


Lets go through thisa one step at a time and check things systematically
even if it involves some apparantly silly checks (sorry) - the post is
slightly ambiguous when you say that you "measured and filled the oil and
petrol correctly" - does this mean that you prepared an oil and petrol
mixture correctly and put this into the fuel tank. If so this is a 2-stroke
mix for 2-stroke engines where as you have a 4-stroke mower. This needs
normal unleaded petrol in the tank and oil is added separately to the crank
case at another location.

Next check the oil level - every 4 stroke engine I have seen has an oil
filler with a dipstick. Put the mower on a level surface and allow to stand
for a while. remove the dipstick, wipe it replace and remove to take a
reading - it should not be too full or too empty which you can check via the
marks on it. Also check that you used the appropriate oil.

If this is all OK then the engine shoudl not be harder to "crank" when it
stops than when cold - as others have said this woudl be due to lubrication
problems. If it is then there is a serious fault with the engine and you
should return to the seller.

Other posters have made other suggestions as to what may be causing it to
stop. How are you using the choke? On most mowers it is only needed for a
few seconds when the engine is first started - the engine will run rough,
stutter and perhaps even stall if it is left on.

How does the engine fade - does it miss, stutter and stall? Does it labour
as if under a lot of laod whic eventuially overcomes the power of the
engine? There is often a clue to the fault there.

You presumably have checked and worked through the instructions. If you
can't get it going and can't find the fault by going through the above then
take it back.

HTH

Hi all, thanks for all the ideas and suggestions.
Ill try and answer them all but its a bit tricky to 'quote' them

Engine is definitely a 4 stroke. It has seperate oil and petrol
reservoirs, and I havent mixed oil/petrol like I understand you do with
2-strokes.
The oil being used is B and Q 4 stroke lawnmower oil.

Im holding down the dead mans handle constantly while mowing, its not
stopping as a result of me leaving go. Admittedly it took me a few goes
to understand this though hehe

I dont think it has a choke as such. Does that make any sense? Ill
double check this.
The pushbar has a control lever on it, saying 'slow, fast, start'.
Maybe the 'start' setting is equivalent to the choke ?
I start the mower and then move this lever to fast, mow for a bit and
it generally cuts out after 30 seconds of this. There is no backfiring
or spluttering, it simply starts slowing down and then stops, in the
space of 4 or 5 seconds.

Does it labour as if under a lot of laod whic eventuially overcomes the power of the
engine?
I guess it could be described as this yes. The grass isnt very long,
but theres bits of uncollected grass lying about from when my electric
mower packed in. It doesnt look as if it should cause an engine much
difficulty though.

Ive read the instruction manual and and following them pretty much to
the letter.

I bought it from B and Q, and given the choice between a mountfield and
this one, I chose this one because it could collapse a bit smaller (Im
limited for space in my shed.) Sorry, I dont know the brand at the
moment, but Im going to be trying with it again today so Ill find out.

Likewise, I havent checked the oil using the dipstick, but I will
today. But I did check it was empty before filling it, and put 600ml in
as the manual suggested. Also put in 1 litre of unleaded petrol.

Im off give it another go, Ill come back with engine power and brand if
its still struggling.

Thanks guys
Paul

Carpii wrote:
Hi all, thanks for all the ideas and suggestions.
Ill try and answer them all but its a bit tricky to 'quote' them

Engine is definitely a 4 stroke. It has seperate oil and petrol
reservoirs, and I havent mixed oil/petrol like I understand you do with
2-strokes.
The oil being used is B and Q 4 stroke lawnmower oil.

Im holding down the dead mans handle constantly while mowing, its not
stopping as a result of me leaving go. Admittedly it took me a few goes
to understand this though hehe

I dont think it has a choke as such. Does that make any sense? Ill
double check this.
The pushbar has a control lever on it, saying 'slow, fast, start'.
Maybe the 'start' setting is equivalent to the choke ?
I start the mower and then move this lever to fast, mow for a bit and
it generally cuts out after 30 seconds of this. There is no backfiring
or spluttering, it simply starts slowing down and then stops, in the
space of 4 or 5 seconds.


Sounds like fuel starvation..try running briefly with the petrol cap OFF
the tank..also make sure that the lever is not still in the start
position...or try running with it there for a while first to let the
engine fully warm up.

Any signs of smokiness at all?


Does it labour as if under a lot of laod whic eventuially overcomes the power of the
engine?
I guess it could be described as this yes. The grass isnt very long,
but theres bits of uncollected grass lying about from when my electric
mower packed in. It doesnt look as if it should cause an engine much
difficulty though.

Hmm. Depends on how good the engine is

Ive read the instruction manual and and following them pretty much to
the letter.

I bought it from B and Q,

Always a mistake ;-)

and given the choice between a mountfield and
this one, I chose this one because it could collapse a bit smaller (Im
limited for space in my shed.) Sorry, I dont know the brand at the
moment, but Im going to be trying with it again today so Ill find out.

Likewise, I havent checked the oil using the dipstick, but I will
today. But I did check it was empty before filling it, and put 600ml in
as the manual suggested. Also put in 1 litre of unleaded petrol.

Mmm.
That sounds OK.

Other than a partially blocked jet, or a vaccum in teh tank causing fuel
stravation, I can;t see what it could be.

Maybe time to take it back and say 'it doesn't work.

Im off give it another go, Ill come back with engine power and brand if
its still struggling.

Thanks guys
Paul

Are you sure it's 4-stroke ? you say it has seperate oil/fuel reservoirs, my
old 2-stroke motorbike had this arrangement and mixed the 2 ensuring a
constant mixture, 600ml of oil sounds about right for this 2 stroke
arrangement but quite low for a 4 stroke engines sump. Do you poor the oil
down the dipstick tube, or is it a seperate tank ?

If it is a 2 stroke that mixes it's own oil/fuel then using 4 stroke oil
will no doubt reduce the lubrication alongside a lean mixture hence the
engine seizing quite quickly.

Pete

"Carpii" wrote in message
oups.com...
Hi all, thanks for all the ideas and suggestions.
Ill try and answer them all but its a bit tricky to 'quote' them

Engine is definitely a 4 stroke. It has seperate oil and petrol
reservoirs, and I havent mixed oil/petrol like I understand you do with
2-strokes.
The oil being used is B and Q 4 stroke lawnmower oil.

Im holding down the dead mans handle constantly while mowing, its not
stopping as a result of me leaving go. Admittedly it took me a few goes
to understand this though hehe

I dont think it has a choke as such. Does that make any sense? Ill
double check this.
The pushbar has a control lever on it, saying 'slow, fast, start'.
Maybe the 'start' setting is equivalent to the choke ?
I start the mower and then move this lever to fast, mow for a bit and
it generally cuts out after 30 seconds of this. There is no backfiring
or spluttering, it simply starts slowing down and then stops, in the
space of 4 or 5 seconds.

Does it labour as if under a lot of laod whic eventuially overcomes the
power of the
engine?
I guess it could be described as this yes. The grass isnt very long,
but theres bits of uncollected grass lying about from when my electric
mower packed in. It doesnt look as if it should cause an engine much
difficulty though.

Ive read the instruction manual and and following them pretty much to
the letter.

I bought it from B and Q, and given the choice between a mountfield and
this one, I chose this one because it could collapse a bit smaller (Im
limited for space in my shed.) Sorry, I dont know the brand at the
moment, but Im going to be trying with it again today so Ill find out.

Likewise, I havent checked the oil using the dipstick, but I will
today. But I did check it was empty before filling it, and put 600ml in
as the manual suggested. Also put in 1 litre of unleaded petrol.

Im off give it another go, Ill come back with engine power and brand if
its still struggling.

Thanks guys
Paul


Sounds like you have done all the right things. Check the oil level and if
it is OK then take it back. Even if fuel starvation you should not be having
these problems given you have been following the manual.