I have a Sovereign Classic 35 lawnmower with a Briggs and Stratton
engine. While cutting the grass last week the engine started to
stutter and finally died on me. First thing I checked was the fuel and
oil levels which seemed to be ok, then the spark plug which was also
ok. Next thing checked was the air filter followed by making sure that
the fuel jet beneath it wasn't blocked. Again, all seemed to be in
order. Getting desperate, I decided to take off the cylinder head and
give both it and the valve seats a good clean up (which they sure
needed!). During the rebuild I made up a new head gasket using the old
one as a template. All this has achieved SFA. I suspect that the
fault is fuel supply related - possibly those two rather flimsy
looking springs under the air filter which operate the butterfly
valve.

Any advice or suggestions would be appreciated.

"teapot" wrote in message
...
I have a Sovereign Classic 35 lawnmower with a Briggs and Stratton
engine. While cutting the grass last week the engine started to
stutter and finally died on me. First thing I checked was the fuel and
oil levels which seemed to be ok, then the spark plug which was also
ok. Next thing checked was the air filter followed by making sure that
the fuel jet beneath it wasn't blocked. Again, all seemed to be in
order. Getting desperate, I decided to take off the cylinder head and
give both it and the valve seats a good clean up (which they sure
needed!). During the rebuild I made up a new head gasket using the old
one as a template. All this has achieved SFA. I suspect that the
fault is fuel supply related - possibly those two rather flimsy
looking springs under the air filter which operate the butterfly
valve.

Any advice or suggestions would be appreciated.

Not done my trick and topped up with the fuel for the chainsaw (2 stroke)?
Check if you are getting a good spark at the plug if it had but still not
firing it may still be worth changing the plug. its not unknown for them to
get tracking.Usually tho when I suspect a plug I pop it on the gas ring for
5 minutes to cook out any hidden fouling obviously if you want to fit it
while still hot ( I do) wear thick gloves!.
Derek

g'day teapot,

never easy trying to suggest things without seeing the machine.

could be that there is water in the fuel tank and as the tank got to
near empty it was sucked into the carby, or the pipes that pick up the
fuel maybe blocked? requires removal of tank/carby assembly and
dismantle of carby for clean out, knowledge is needed for reassembly,
and you most likley will need a new diaphram on re-assembly, the
problem could be the diaphram. unless you know where the springs fit
and how and the diaphram and it's componenets this job better left to
a mechanic if deemd necessary. any damge to or incorrect installation
of those govenor springs will mean the mower won't run as it should.

might also mean that the intake valve in particular needs re-gapping,
when you ahd the head off and with the intake valve seated did you
check to see that you couldn't rotate the valve using finger pressure,
or take the valve cover off and using feeler guges check the air gaps
should be about 7 thousands of an inch (not sure of the metric
measure). if gapping is needed again that requires some expertise.

also what was wrong with the original head gasket? head gaskets can be
used a number of times, just soak it in hot water while you fiddle
around. your homemade gasket may not be the same construction as the
original.

and as has been said check the spark but if it is a more modern mower
then it should have an electronic ignition which if faulty will need
replacement usually expensive. and those spark plugs may look ok but
that doesn't mean they are working, especially under compression loads
in the motor. and air space checking of spark doesn't tell you the
strength of the spark, though if it is a blue clour and jumps say 1/4"
then it could be considered to be sufficient.

if you perservere with home repair might be wise to obtain a service
manual, for reference one might be available from your local library
or do a google you might get one from online. you will need the engine
numbers stamped onto the side of teh engine cowling in most cases.

let us know the end result

On Thu, 15 May 2008 04:30:22 -0700 (PDT), teapot
wrote:
snipped
With peace and brightest of blessings,

len & bev

--
"Be Content With What You Have And
May You Find Serenity and Tranquillity In
A World That You May Not Understand."

http://www.lensgarden.com.au/

In message
,
teapot wrote
I have a Sovereign Classic 35 lawnmower with a Briggs and Stratton
engine. While cutting the grass last week the engine started to
stutter and finally died on me. First thing I checked was the fuel and
oil levels which seemed to be ok, then the spark plug which was also
ok. Next thing checked was the air filter followed by making sure that
the fuel jet beneath it wasn't blocked. Again, all seemed to be in
order. Getting desperate, I decided to take off the cylinder head and
give both it and the valve seats a good clean up (which they sure
needed!). During the rebuild I made up a new head gasket using the old
one as a template. All this has achieved SFA. I suspect that the
fault is fuel supply related - possibly those two rather flimsy
looking springs under the air filter which operate the butterfly
valve.

Any advice or suggestions would be appreciated.

On my mover the gauze fuel filter being almost completely blocked with
'gunk' caused the same problem. Remove the carburettor and the filter
will be on the part that pokes into the fuel tank. I pulled off the
filter and washed it in clean petrol using a paint brush.

Check also the state of the petrol in the fuel tank I also cleaned out
some rubbish in the tank (probably emulsified water contamination) with
clean petrol.

While you have the caberator/petrol tank apart consider replacing the
rubber seal between them as this can also perish causing similar
problems.
--
Alan
news2006 {at} amac {dot} f2s {dot} com

teapot wrote:
I have a Sovereign Classic 35 lawnmower with a Briggs and Stratton

FWIW I have just had a mower fuel problem that turned out to be caused
by 'old' petrol. according to the mower repair shop modern unleaded
petrol goes off after approx 12 weeks. Mine had been serviced in the
autumn and came to use it two weeks ago filled it up with last years
petrol - no water or contaminants - and would start but not run.
Apparently this is a common fault and some engines like my Honda are
more prone to this than others.

On 2008-05-16 10:13:24 +0100, Yuri said:

teapot wrote:
I have a Sovereign Classic 35 lawnmower with a Briggs and Stratton

FWIW I have just had a mower fuel problem that turned out to be caused
by 'old' petrol. according to the mower repair shop modern unleaded
petrol goes off after approx 12 weeks. Mine had been serviced in the
autumn and came to use it two weeks ago filled it up with last years
petrol - no water or contaminants - and would start but not run.
Apparently this is a common fault and some engines like my Honda are
more prone to this than others.

Yup. With my Mountfield petrol mower, every spring I would need to
empty out any remaining fuel and replace with fresh, then also take the
spark plug out and bake it in the oven for a while. If I didn't do
this, there was no way in the world it would start, but with this
procedure, it always started on the first pull.

On Fri, 16 May 2008 11:38:47 +0100, adm wrote and
included this (or some of this):

On 2008-05-16 10:13:24 +0100, Yuri said:

teapot wrote:
I have a Sovereign Classic 35 lawnmower with a Briggs and Stratton

FWIW I have just had a mower fuel problem that turned out to be caused
by 'old' petrol. according to the mower repair shop modern unleaded
petrol goes off after approx 12 weeks. Mine had been serviced in the
autumn and came to use it two weeks ago filled it up with last years
petrol - no water or contaminants - and would start but not run.
Apparently this is a common fault and some engines like my Honda are
more prone to this than others.

Yup. With my Mountfield petrol mower, every spring I would need to
empty out any remaining fuel and replace with fresh, then also take the
spark plug out and bake it in the oven for a while. If I didn't do
this, there was no way in the world it would start, but with this
procedure, it always started on the first pull.


Whereas with my 10 year-old Hayter (unleaded petrol rotary) it's been
left with fuel in the tank every winter. I've never had the plug out
and it starts easily in the spring after priming. I give the engine
oil a bit of a top up occasionally and that's all the maintenance it
gets. Touch wood.


--
®óñ© © ²°¹°-°²

On 16 May, 08:10, Alan wrote:
In message
,
teapot wrote

I have aSovereignClassic 35lawnmowerwith a Briggs and Stratton
engine. While cutting the grass last week the engine started to....

On my mover the gauze fuel filter being almost completely blocked with
'gunk' caused the same problem. Remove the carburettor and the filter
will be on the part that pokes into the fuel tank. I pulled off the
filter and washed it in clean petrol using a paint brush.

Check also the state of the petrol in the fuel tank *I also cleaned out
some rubbish in the tank (probably emulsified water contamination) with
clean petrol.

While you have the caberator/petrol tank apart consider replacing the
rubber seal between them as this can also perish causing similar
problems.

Thanks for all the responses. I know its not the plug as it works fine
in my neighbours mower, but I will follow up your suggestions
regarding the fuel system.

On 15 May, 12:30, teapot wrote:
I have a Sovereign Classic 35 lawnmower with a Briggs and Stratton
engine. While cutting the grass last week the engine started to
stutter and finally died on me. First thing I checked was the fuel and
oil levels which seemed to be ok, then the spark plug which was also
ok. Next thing checked was the air filter followed by making sure that
the fuel jet beneath it wasn't blocked. Again, all seemed to be in
order. Getting desperate, I decided to take off the cylinder head and
give both it and the valve seats a good clean up (which they sure
needed!). During the rebuild I made up a new head gasket using the old
one as a template. All this has achieved SFA. *I suspect that the
fault is fuel supply related - possibly those two rather flimsy
looking springs under the air filter which operate the butterfly
valve.

Any advice or suggestions would be appreciated.

Hi - have you ruled out a sticking float.
Steve

On Fri, 16 May 2008 11:38:47 +0100, adm wrote:

Yup. With my Mountfield petrol mower, every spring I would need to
empty out any remaining fuel and replace with fresh, then also take the
spark plug out and bake it in the oven for a while.

Did our "lawn" last week. First time the mower had been used since Oct or
Nov last year. Checked the oil looked at the plug (but didn't do anything)
filled it with petrol from the can last used Oct/Nov. Primed it pulled,
nothing, repeat twice and off it went I suspect I didn't prime it enough
to refill the chambers in the carb. Bog standard B&S engine, probably
what you have on the "Mountfield".

It might be a bet more interesting starting the two stroke strimmer, that
only got two or three outgings last year and hasn't be used for a lot
longer than the mower.

--
Cheers
Dave.

hi. i have a lawnking and im working on a problem the same as you. you should take the carb apart, and the little brass bit unscrew that and drain the fuel out of that bit. becasue when i drained the fuel out of mine a load of dirt came out with it. and if that does not work i would take the fly wheel off and take a good look underneath it. and the main thing is the petrol okay?

hi i found out the problem on my lawnmower. it was the air filter. Take it out and it should run. after that try cleaning it up. or you may just have to get another one. but dont use the machine with out an air filter in dusty conditions.

Regarding the same model - the blade drive belt cover of my mower is broken - where do i go for a replacement part?
Any advice or suggestions would be appreciated.[/quote]


[quote=teapot;791862]I have a Sovereign Classic 35 lawnmower with a Briggs and Stratton
engine. While cutting the grass last week the engine started to
stutter and finally died on me. First thing I checked was the fuel and
oil levels which seemed to be ok, then the spark plug which was also
ok. Next thing checked was the air filter followed by making sure that
the fuel jet beneath it wasn't blocked. Again, all seemed to be in
order. Getting desperate, I decided to take off the cylinder head and
give both it and the valve seats a good clean up (which they sure
needed!). During the rebuild I made up a new head gasket using the old
one as a template. All this has achieved SFA. I suspect that the
fault is fuel supply related - possibly those two rather flimsy
looking springs under the air filter which operate the butterfly
valve.

Hi, I had a similar problem and I found this dvd that solved this problem, I got a copy on ebay but the website is Repairing Lawn Mowers For Profit - Repairing Lawn Mowers For Profit I've actually made some money doing this as well and I know nothing about repairing lawnmowers. Hope this helps."

I think you need to buy a new diafram (Excuse spelling) for the Carbureter at a cost of about £6 and this will solve your problem. They need to be changed nearly every year. Very easy to install, remove tank and carb from lawn mower by removing two bolts and remove top of carb and replace