# Petrol lawnmower



## nudda (Oct 28, 2008)

not sure if this is the right section but ill keep going 

I got a new MTD lawnmower a few months ago. Used it once and it was fine. Knew I wouldnt be using it for a while so put it in storage with fuel out. Today the weathers good so though Id get the garden in shape and the blased thing doesnt start. I prime it a few times and when I pull the cord to start it does run for about 2 second. A lot of smoke comes out the exhaust and it shuts down.

I've tried:-

opening and closing the carberueter - nothing to clean as it looks whistle clean.

Used new fuel

Cleaning filter

Making sure enough oil is in there (there is and its v clean)

cleaning spark plug (although again thats near enough brand new).

I just cant get it to work. Anyone know what it may be?
It's an MTD S46 PB

Thanks


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## macca666 (Mar 30, 2010)

How often have you ran it when it does start for a couple of seconds?

My petrol lawnmower, can't remember make sorry, does similar after its had its winter break. I generally run it for the couple of seconds a few times and it runs longer each time until it runs without cutting out.

I need to do it on my slabs rather than the grass as well and I just raise the cut height to its highest just to be safe.


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## nudda (Oct 28, 2008)

ive tried it about 10 times and it does the same each time
I did read somewhere a few other things to try:-

* Leaving petrol cap slighly open - could be vent is clogged.
* one the engine starts for a bit, keep priming until stable
* Removing air filter so theres no obstruction.


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## nbray67 (Mar 22, 2012)

Does it not have a choke to aid cold starting?

If it does, it could be that the choke is not set correctly or possibly stuck open/closed.

Also, is the oil level all ok?


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## shine247 (Mar 1, 2010)

Probably a wild card but have you tilted it at some point to the extent oil has entered areas it would not when level. Not sure what engine you have but B&S do that and it cloggs up the exhaust. The combination of that and little use may be it.


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## nudda (Oct 28, 2008)

no choke aid. Just a primer. Oil levels perfect.

Could be that the oil has gone in places it should be as its done a 360 in my hands lol. I have tried the other points I mentioned and nothing has worked. When it starts and I keep pressing primer, it works but continues to chuck out lots of smoke. 

Days coming to an end. Im accpeting it will not happen today


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## camerashy (Feb 9, 2014)

Mine is a pig to start after Winter Suffolk Punch keep trying with the choke closed then open it and try again
It may be that the spark plug is wet so give it time to dry out 
Seems as if you are doing everything else OK
Unleaded petrol??


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## jimi_boom (Dec 28, 2010)

how have you stored the lawn mower, Was it in the as used state with the motor in its normal horizontal position?
What make is it, I have seen virtually new cheapo models needing a full carb re build due to cheap materials before. 
What does the plug look like is it soaking wet?


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## nudda (Oct 28, 2008)

Its working!!! I kept priming it while it was on for a bit and eventually smoke disappeared and it stays on. Whoo hooo! Persistance pays off. Thanks all for your help!


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## DLGWRX02 (Apr 6, 2010)

I know its working now, but i had to get the father in laws rotavator (think its a 7 hp B&S motor) going again after he left it outside ALL WINTER under a tarpaulin! After trying the obvious air filter, carbs, new plug a bit of easy start etc, I ended up dragging it into his garage and putting a fan heater on it for an hour or so to warm it up. Eventually it fired up and ran for as long as i needed it then it fired up first pull every time after.


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## Rayaan (Jun 1, 2014)

Mine does the same thing - seems to blow loads of smoke when oil is topped up as well. 

Seems to be fine after a few runs.


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## Sh1ner (May 19, 2012)

A lot of these carbs have small internal diaphragms which pump the fuel in time with the engine.
When left without fuel or the fuel has dried out it allows the diaphragm to go hard and not pump.
Once fresh fuel has been incontact with it for a while it then softens and pumps correctly and the engine keeps running. So it it worthwhile on first start up after a layoff to allow the petrol to soak and soften everything for a while before trying to start. 
Briggs and Stratton lawnmower engines/carbs used to be designed such that, with fuel in the tank and the tap on, if you tip the mower by the handles until it is vertical for a second or two and then return to level, some fuel will run over the diaphragm fill the chamber. prime the engine and soften the diaphragm all at the same time.
After a while some diaphragms stretch and no longer pump or particularly with B+S engines the carb top housing bows, no longer seals and leaks air causing non starting or poor running.


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