The Great Big Lawnmower Thread

fryup

fox0512 wrote: »

The backfire is fuel entering the muffler when you turn engine off, this can be a fuel solenoid issue if your carb has a solenoid....

there was a big plume of smoke when i tried to start it again, so i presume it must be that then

so its just a case of changing it?

Eamondomc

my3cents wrote: »

What engine? Many do just look at where the fuel tank is and if its that same height or below the carb then it will have a fuel pump of some kind. If the fuel at the bottom the tank is below the level of the carb then how can it flow without a pump?

Ok, my tank is high, was just checking that there wasn't something there I didn't know about. Tnx

fox0512

fryup wrote: »

there was a big plume of smoke when i tried to start it again, so i presume it must be that then

so its just a case of changing it?

Black or white smoke ? If black then yes she flooding.. Remove carb and check float

my3cents

fryup wrote: »

there was a big plume of smoke when i tried to start it again, so i presume it must be that then

so its just a case of changing it?

You can test it first. Just take it out and turn the ignition. Obviously do the necessary to stop the fuel p!ssing out everywhere and a spark igniting it.

You can also often see it working if you open up the card which you may find has some corrosion in it afaik that can be due to water in the petrol and bad storage (fuel left in carb over winter ).

fox0512

if the needle is unable to seal jet/seat correctly the carb will keep asking for fuel...in this situation i would also check your oil...a carb thats flooding can give you petrol entering at the head and making its way past piston etc and down to sump....no big deal if this happens...fix carb first and change your oil if theres a smell of fuel from it

fryup

fox0512 wrote: »

Black or white smoke ? If black then yes she flooding.. Remove carb and check float

yes black, carb could also be blocked? all though a fuel filter should prevent this?

my3cents

fryup wrote: »

yes black, carb could also be blocked? all though a fuel filter should prevent this?

As mentioned above bad storage and any aluminium in the carb can corrode from water in the fuel.

fox0512

at this stage there is only one thing you need to do..get carb off and check float...if its doing what i explained before then thats why your flooding...

fox0512

If carb is blocked you wouldnt get any black smoke because fuelis unable to reach spark plug....in this case your have fuel reachin it but to much

yop

my3cents wrote: »

Fuel leak somewhere most rideons these days have a fuel pump that will leave the fuel lines under slight pressure when you switch off. Maybe you are using enough fuel while its running not to have a noticeable leak?

Nothing noticeable on it, its running smooth and fuel usage seems the same. I will check the lines.

fryup

i checked needle & float everything A ok

however the fuel solenoid when i tested it with ignition the pin goes in ..but stays in when switched off

but pressing it with my finger pin moves in & out freely

fox0512

fryup wrote: »

i checked needle & float everything A ok

however the fuel solenoid when i tested it with ignition the pin goes in ..but stays in when switched off

but pressing it with my finger pin moves in & out freely

Make sure its clean and no gunk/rust on it....thats what they will do when going bad they lose magnetism...the pin stayin down is causing your backfire when you turn engine off... some engines are more prone to it than others...but this shouldnt effect the engine when running...if engine send out black smoke on start up the needle although it make appear fine may be letting some juice past or the carb is running a little rich...a common enough complaint on older machines as jets get older.... the solenoid is just to prevent back fire and should not cause flooding in your carb...

fox0512

Id give her a fresh solenoid if you dont like backfires and a needle and seat and i reckon it will be sorted....the carb doesnt need the solenoid to run..

fryup

can they be taken apart and new spring put in?

they cost up to €70 new:(

its one like this

fox0512

fryup wrote: »

can they be taken apart and new spring put in?

they cost up to €70 new:(

its one like this

Ill have a look and see do i have a spare....70notes!!!!

http://www.ebay.ie/itm/GENUINE-Briggs-Stratton-692734-Fuel-Solenoid-Replace-497672-497157-495739-/121980066393?hash=item1c66941a59:g:b1cAAOxy4dNSxOIa

fox0512

remember that a new one will only stop backfires and engine will run fine without it....just block the ears

fox0512

Id def give her needle and seat first before spending on a solenoid....

fryup

how do you get those seats out??

fox0512

fryup wrote: »

how do you get those seats out??

best thing to do is head for youtube... some good vids there will help a lot...hard to explain in text as good as a vid..

give carb a good clean when its off too

fryup

i don't mean to flog a dead horse here...

but i still don't understand why the pin of the carb solenoid doesn't go back up when i switch ignition off...but yet goes up & down freely when i press it with my finger??

fox0512

fryup wrote: »

i don't mean to flog a dead horse here...

but i still don't understand why the pin of the carb solenoid doesn't go back up when i switch ignition off...but yet goes up & down freely when i press it with my finger??

Finger to one side for a min as its just manual manipulation ...

when it receives 12v a magnetic field is created which draws pin down....there is an issue in the sol wont allow the pin to rise via loss of current.. some solenoids that go bad the pin will rise after 10/15 min closing off jet and mower dies...Im not an expert on them but id imagine something has shorted or grounded out in there to mess up magnet..

fox0512

Even with a good sol the pin will rise an fall manually with ease...prob with backfire is i forget everytime its going to happen and in the workshop the sound is multiplied so i make a girlie sound then ringing in the ear

fryup

thanks lads got it sorted,

cleaned out the carb and fitted a second-hand fuel solenoid on and everything "seems" to be honky dory...no backfires, no flooding:)

but ...just one thing my battery is getting no charge...gammy voltage regulator??

my3cents

fryup wrote: »

thanks lads got it sorted,

cleaned out the carb and fitted a second-hand fuel solenoid on and everything "seems" to be honky dory...no backfires, no flooding:)

but ...just one thing my battery is getting no charge...gammy voltage regulator??

I'd be looking at connectors first, twas the problem I had recently.

fox0512

Yup.. No lose connections at battery and batt neg has a good ground...check wiring etc... If you have a multimeter you can check if the batt is receving charge.. At around mid rpm you should get a reading of 14v ish

fox0512

Yup.. No lose connections at battery and batt neg has a good ground...check wiring etc... If you have a multimeter you can check if the batt is receving charge.. At around mid rpm you should get a reading of 14v ish

Needles73

fryup wrote: »

thanks lads got it sorted,

cleaned out the carb and fitted a second-hand fuel solenoid on and everything "seems" to be honky dory...no backfires, no flooding:)

but ...just one thing my battery is getting no charge...gammy voltage regulator??

What makes you think battery not getting a charge ? Is it that engine stops if you disconnect battery ?

my3cents

fox0512 wrote: »

Yup.. No lose connections at battery and batt neg has a good ground...check wiring etc... If you have a multimeter you can check if the batt is receving charge.. At around mid rpm you should get a reading of 14v ish

It was the connections between the alternator and the rectifier/regulator I was thinking of because they are often left exposed on the side of the engine.

Lost of information found here https://www.briggsandstratton.com/content/dam/briggsandstratton/na/en_us/Files/FAQs/alternator_replacement.pdf possibly to much information.

Man of Aran

my3cents wrote: »

It was the connections between the alternator and the rectifier/regulator I was thinking of because they are often left exposed on the side of the engine.

Lost of information found here https://www.briggsandstratton.com/content/dam/briggsandstratton/na/en_us/Files/FAQs/alternator_replacement.pdf possibly to much information.

Agree with you and FoxO, the OP might have disturbed connector block or the ground cable when he went at the carb repair.
Was it charging Ok before he went at the carb issue would be starting point in diagnosis, if so then retrace steps!
A lot of good and helpful info on this thread lads,,,,, keep it up.
One that comes to mind is the 40:1 mix for 2 Stroke garden tools as being a good all-round ratio that one of ye suggested here. I tried it and you know what, many tools now run sweet as a nut where they were slow to start or sluggish before.

fryup

Needles73 wrote: »

What makes you think battery not getting a charge ? Is it that engine stops if you disconnect battery ?

the battery light comes on dash, and in user manual it says that indicates insufficient charge

*and it started before carb problem