Briggs and Stratton not starting....
Discussion
Yes its that time of year again. The lawnmower came out of Hibernation last weekend, got taken apart, had a rough coat of paint on the bad bits and a service. I bolted it all back together just before the MotoGP to try and get it running but it wouldn't start.
The engine hasn't run properly since some donkey stuck petrol in the oil tank a couple of years ago, but I have drained down the sump, and refilled with some lovely fresh oil, some fresh UL and a new spark plug but no joy. I air intake is covered in a black residue, looks a bit like carbon and some carb cleaner has begun to shift it, but obviously this process is easier when the engine is running.
The throttle mechansim is also sticking slightly, but it isn't presenting too much of a problem. I need to get the damn thing running, I decided to leave the blade off the shaft until it was running again in case I had to take the engine off the chassis again, i am wondering whether this is having an adverse effect.
Any ideas??
TIA
Stuart.
The engine hasn't run properly since some donkey stuck petrol in the oil tank a couple of years ago, but I have drained down the sump, and refilled with some lovely fresh oil, some fresh UL and a new spark plug but no joy. I air intake is covered in a black residue, looks a bit like carbon and some carb cleaner has begun to shift it, but obviously this process is easier when the engine is running.
The throttle mechansim is also sticking slightly, but it isn't presenting too much of a problem. I need to get the damn thing running, I decided to leave the blade off the shaft until it was running again in case I had to take the engine off the chassis again, i am wondering whether this is having an adverse effect.
Any ideas??
TIA
Stuart.
The blade being off shouldn't make a difference.
2 things you need to establish really
Spark generation
fuel delivery
stick an old spark plug in the connector and earth it on the chassis, have someone pull the starter cord........do you see a spark? if so what colour is it?
if you use the little primer bulb (red on mine) does it feel like it's pumping petrol up to the float chamber?
from there.....is the needle valve allowing the fuel INTO the float chamber?
Is the main jet gummed up?
lawnmowers should be drained of petrol over the winter break ideally to prevent gumming.
is this a 4 stroke motor or a 2 stroke?
2 things you need to establish really
Spark generation
fuel delivery
stick an old spark plug in the connector and earth it on the chassis, have someone pull the starter cord........do you see a spark? if so what colour is it?
if you use the little primer bulb (red on mine) does it feel like it's pumping petrol up to the float chamber?
from there.....is the needle valve allowing the fuel INTO the float chamber?
Is the main jet gummed up?
lawnmowers should be drained of petrol over the winter break ideally to prevent gumming.
is this a 4 stroke motor or a 2 stroke?
Thanks for the reply brian.
Will check for a spark, forgot about that bit!
No primer bulb on my engine.
Its a 4stroke 3.5hp B&S engine from the early 80's IIRC!
ATM the airbox is off the Carb so I can clean the flap bit. When I was turning the engine over the petrol was pretty much free flowing. No sign of blockage in the fuel line. The Fuel seems to be pumped from the tank which sits under the and to the side of the carb, the fuel line comes up and outside to a right angle, then into the carb.
I somehow think this may be a sparking issue, but wouldn't know where to start!!
Will check for a spark, forgot about that bit!
No primer bulb on my engine.
Its a 4stroke 3.5hp B&S engine from the early 80's IIRC!
ATM the airbox is off the Carb so I can clean the flap bit. When I was turning the engine over the petrol was pretty much free flowing. No sign of blockage in the fuel line. The Fuel seems to be pumped from the tank which sits under the and to the side of the carb, the fuel line comes up and outside to a right angle, then into the carb.
I somehow think this may be a sparking issue, but wouldn't know where to start!!
Hi again m8
I nearly forgot.....Briggs and stratton have an excellent website, when I bought my mower i noticed a trouble shooting section.
www.briggsandstratton.com/display/router.asp?DocID=65847
That link might just help you.
if not, post back and i'll see what I can come up with for you.
I nearly forgot.....Briggs and stratton have an excellent website, when I bought my mower i noticed a trouble shooting section.
www.briggsandstratton.com/display/router.asp?DocID=65847
That link might just help you.
if not, post back and i'll see what I can come up with for you.
tvradict said:
Its a 4stroke 3.5hp B&S engine from the early 80's IIRC!
Scrap it, they're shite. Briggs and Scrap'em is the usual term...
Strip down the carb and make sure all the nasty little rubber flappy things that are supposed to be valves are working - that mechanism for pumping the petrol up to the float chamber is completely crap and doesn't work at cranking speeds. Check the spark and give it a new plug.
If it doesn't behave any better try pulling it over with your hand over the air intake.
If it still doesn't work scrap it and get a Honda, or one of the B&S models that came out in the 90s and are basically rebadged Hondas.
Always found that (assuming valve not stuck and you have spark and fuel) putting spark plug in the oven and roasting gently on medium for a couple of minutes does the trick. You've got to don the asbestos gloves and get it back in the head quick before it cools down but should then start on first pull.
My 2 stroke flymo always suffers from a gummed up primary jet (becuase i never bother to press the little button that drains the fuel out of the carb, always assuming that i will be cutting the grass again the following week)
Infact ive got a little collection of spare engines for it, every so often i see them down at the local tip, if your'e quicker than the pikey's, you can pick em up for a £5.
Eliot.
Infact ive got a little collection of spare engines for it, every so often i see them down at the local tip, if your'e quicker than the pikey's, you can pick em up for a £5.
Eliot.
gdr said:
Always found that (assuming valve not stuck and you have spark and fuel) putting spark plug in the oven and roasting gently on medium for a couple of minutes does the trick. You've got to don the asbestos gloves and get it back in the head quick before it cools down but should then start on first pull.
A gas blow lamp is much quicker and easier!
Main jet is my best guess
whip the float bowl off and have a butchers, on my latest steed "it´ll never run again mate
" the main jet is up the middle of the float chamber, the bolt holding on the chamber covers bolted into the jet. Cleaning the nut and a quick squirt of Widdy Diddly and we were up and running
Had to modify the suspension this year, as part of the chassis had collapsed, but it,s still going
whip the float bowl off and have a butchers, on my latest steed "it´ll never run again mate
" the main jet is up the middle of the float chamber, the bolt holding on the chamber covers bolted into the jet. Cleaning the nut and a quick squirt of Widdy Diddly and we were up and running Had to modify the suspension this year, as part of the chassis had collapsed, but it,s still going
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