poxi mower wont run fo r 30 secs

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big bream

scott
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any one had any probs with the mcculock petrol mower as mine has dedided it will only run for 30 secs then stall ive tryed cleaning out the fuel tank carb ect still the same [:H][:H][:H][:H][:H][:H][:(!][:(!][:(!][:(!][:(!][:(!]
 

Dave

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Blocked air filter ?
 

crusty

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With 30 second bursts you could watch it grow behind you as you went along. You could have a lawn wave going on.

If its not the fuel or air intakes then it has to be electrics, plug or HT lead is my guess.



Ian
 

chrishowe425

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petrol in it new or been in it a while?

it can go a bit funny if its been stored to long.

could be something simple like a partially blocked fuel line.
 

Neil ofthe nene

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Does it have a safety brake? It could be that that is re-engaging with the vibration.

Other than that it really can only be fuel supply. Using up what's past the blockage before stopping. Can you re-start it immediately it stops or do you have to wait?
 

nobby478

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This is almost certainly a failed diaphram in the carb.

A few years ago they needed replacing every year as something in our UK fuel was rotting them. Now it seems OK again. I propably do one each Spring instead of 20 ! [:0]

I'm not familiar with your machine, but I suspect it uses a Briggs and Stratton motor with a plastic carb on top of a metal fuel tank?. If so, the diaphram is between carb and tank.

A lot of mowers use this Malaysian built engine as they are very cheap to buy in.


One thing to watch on all mowers is that you don't soak the air filter in engine oil when dragging it about or cleaning it, Honda are the worst for this.



HTH
 

davej

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Check the breather hole in the petrol cap isn,t blocked, might be creating a vacuum in the tank.
 

big bream

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Originally posted by nobby478

This is almost certainly a failed diaphram in the carb.

A few years ago they needed replacing every year as something in our UK fuel was rotting them. Now it seems OK again. I propably do one each Spring instead of 20 ! [:0]

I'm not familiar with your machine, but I suspect it uses a Briggs and Stratton motor with a plastic carb on top of a metal fuel tank?. If so, the diaphram is between carb and tank.

A lot of mowers use this Malaysian built engine as they are very cheap to buy in.


One thing to watch on all mowers is that you don't soak the air filter in engine oil when dragging it about or cleaning it, Honda are the worst for this.



HTH
well after having the carb off twice last night and running it without the air filter which made no diference i noticed the air filter sponge was soaked in oil so i washed it out in petrol left it over night hey presto now she runs a dream they are obveously critical for there air flow [:D]
 

big bream

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Originally posted by big bream

Originally posted by nobby478

This is almost certainly a failed diaphram in the carb.

A few years ago they needed replacing every year as something in our UK fuel was rotting them. Now it seems OK again. I propably do one each Spring instead of 20 ! [:0]

I'm not familiar with your machine, but I suspect it uses a Briggs and Stratton motor with a plastic carb on top of a metal fuel tank?. If so, the diaphram is between carb and tank.

A lot of mowers use this Malaysian built engine as they are very cheap to buy in.


One thing to watch on all mowers is that you don't soak the air filter in engine oil when dragging it about or cleaning it, Honda are the worst for this.



HTH
well after having the carb off twice last night and running it without the air filter which made no diference i noticed the air filter sponge was soaked in oil so i washed it out in petrol left it over night hey presto now she runs a dream they are obveously critical for there air flow [:D]
what is that plastic carb all abt never seen any thing like it
 

big bream

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i know dave i thought by removing it would eliminate the problem erm obveously not der
 

spanky

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I can sympathise with this problem, still haven't got to the bottom of it though.

I've found running it with a little redex in the fuel gets it going eventually, but it's still lacking power. It's got new fuel, plug, oil and air filter and the sump of the carbs been checked for gunk (it was clean), I suspect a fuel feed problem, but I think it's beyond my skills to strip down. (Briggs & Stratton 4 stroke Quantum if that helps).
 

Dave

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The problem with most petrol lawnmowers is that they're left sat over winter with last year's fuel in the tank.
The petrol evaporates and leaves a laquer on the sides of the tank plus any dirt settles to the bottom.
Once the mower is dragged out of it's hibernation and filled with new fuel, the laquer breaks away from the sides and on first pull the dirt that's now settled and caked at the bottom of the tank gets dragged into the carb.

The best thing you can do before putting it away for winter is to empty the fuel tank, likewise if you've left any in over winter is to empty it first and then clean out the settled dirt.
Sometimes you can be lucky and it'll start on a few pulls and run properly, othertimes it doesn't and it's time to start cleaning out the fuel tank and the carb jet
 

nobby478

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Dave's advice is spot-on.


Either empty the fuel tank or fill it to the brim when laying the mower up for the Winter.


Soaked oil filter....that'll be sump oil sploshed up onto it when moving the mower around.


Plastic carbs? The Briggs and Stratton two-strokes with the red rubber bulb on it have them. The bulb is for priming the engine with fuel instead of a choke. I'm told these engines cost 9 to make !! [:0] It was these that needed new diaphrams...they use crankcase vacum to lift the fuel from the tank into the carb body...when they fail the engine uses the fuel in the carb but can't replenish it quickly enough..hence the running for 30 seconds before dying. It is temporarily fixed by filling the tank up as the daiphram doesn't have to work so hard, ....but as the fuel tank level drops, -back comes the problem.

These were the simplest of engines with no throttle to work, just a govenor
There is another version of the engine with a throttle you operate yourself..they seemed less prone to the diaphram failing.



It's a bit of a disgrace the way fuel is changed in this country without a by-your-leave. A similar change in the 80's meant bikes stalling with 'carb icing'. I had to go to the Royal Courts of justice and give evidence on behalf of Kawasaki when one guy sued them over a crash.

I later learned that our fuel had been changed to suit colder climates like Finland ! Kawasaki, in the meantime, had spent millions putting new carbs on every water-cooled bike they ever made. I must have done many hundred carb changes myself during this period ... all under warranty.
 

Minipeace

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The reason why you have oil in the filter is you may have laid the mower on its filter side which allows the oil to run into the filter.

Never leave your mower with fuel in the tank over winter. You need to run it dry as the fuel will dry and fur up your pipes and carb. All the mowers I use are run dry but the Etesia mower has a on and off petrol flow switch to aid running carb dry but its commercial and not diy stuff.
To winter store you do this.
clean underdeck (remove spark plug cap)
check airfilter is clean and good
remove spark plug and pour one soup spoon of oil into cylinder
turn engine over by a few hand pulls and if possible try to do this with the blade engaged so it too turns.
replace plug
store in a dry place

To restart remove spark plug and clean out with petrol.
allow it to dry and do not replace spark plug yet
pull starter to expel oil from engine
then replace plug and start engine.

The golden rule is 3 months on fuel but briggs do a tablet to maintain the fuel if you do wish to store the fuel for longer periods.

I do this with all my mowers and they soon start after a winter store but I also change the oil before winter storage too but I do regular oil changes through the season.

Briggs have changed their engine design and most now are starting to have a simple pull and start system where the choke is auto and controlled by a simply spring system. My Hayter has their commercial engine and is very easy to start but has a choke setting.
The John Deere one I also have is not as good but its not commercial but it does the job but is a little lacking in power but good pickup. The Etesia is just different and is a dream to use as it has a super collection and a great Honda engine.
 
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the gaffer

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most of these diaphragms are usually just gone out of shape at the back,look at the diaphragm where it clamps between the carb and the tank and you will see at the back against the engine that it is often just gone out of shape and sucking in air,mainly because of heat and vibration loosens the screws over time,often simply straightening it and making sure it sits where it should and tightening the carb back down will cure the problem.regardless of what is often said,these engines when looked after are far better than most other engines you find on any mowers.like so many other things though, abuse it and you lose it.
 

big bream

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yes i think they must be quite reliable i have had mobile air compressors in my on site service vans for abt 11 years now they have allways been briggs engines the only prob i had was a carb gasket leak never even replaced the plug and these comps get a hammering day in day out.
 
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