I have a mountfield powered lawn mower. On trying to start it after storage over the winter the engine starts, runs perfectly for 15 seconds and then stops. It won't start again immediately but if you wait a few minutes it then starts again, runs for 15 seconds and then stops. I have checked fuel is getting through to the carburettor. Any ideas?
i have a honda 135 starts first time runs most of the day then the engine starts to struggle almost like there's no fuel in the tank had the spark plug changed drained the carb but still does it any ideas
steve, May 2012
It needs the Carb cleaned. Mine was doing the same.
Jason, October 2010
my lawn mower keeps on reving up and down by it self
andy, May 2010
yes I have the same problem but runs for about two minutes. When its cooled down it starts again. Has been to the repair shop twice for carburetta cleaning but only slight improvement. Have been mowing the lawn in short bursts but now only runs for that short time with the choke full on. My first thought was the plug actually. but the plug spark seemed ok and the terminal is not soot black as you would expect with poor ignition. Still I will get a new plug after reading all your comments. Will update you.
clive, April 2010
YES I HAVE THE SAME , I THINK IT MIGHT BE THE COIL
I ALSO HAVE CLEANED OUT THE CARB, I JUST NEED TO CHECK IF THERE IS A BUILT IN CRANK CASE OIL CUT OFF SWITCH .IF YOU FIND ANY MORE INFO COULD YOU LET ME KNOW. DAVE
DAVE HALE, May 2009
Spent all afternoon pratting around with all the same, stripped carb, checked fuel line, even checked plug and all looked fine. Thanks to all the info here I will go and get a new plug instead of wasting tomorrow on more of the same.
Steve, April 2009
I had the same problems as above... ditto ditto ditto! I got myself a new plug and she's now running like a bird again!
Thank you so much bloggers...You've save me a bomb I'm sure of that!
Don ...Bristol., March 2009
Same symptoms for me, again cured by new spark plug. Only difference from last week (when it was working) was that I refuelled with some old petrol that I found.....
Colin, August 2008
Same problem - mower was dragged out last weekend having done last year successfully but now would not start.
Again I pulled the carb apart and blew out the jets. On reassembly it started first pull but only ran for some 15 seconds and then stopped. It will restart a few minutes later, on choke, and run for another 15 seconds and stop.
It seems the filler cap vent solution was a red herring.
I am convinced it is something to do with the vacuum control on the throttle rather than fuel delivery....
Anyone got any thoughts on this? There are numerous instances of this fault on many forums - someone MUST know what is causing this is.
ZZ_von_Schnerk, May 2008
I had the same problem with mine ,adjusting the gap of the spark plug cured the problem for this moment.But I'm going to install a new one.
Kees (holland), July 2007
Mike, I have the same problem. Did changng the spark plug work for you? My engine's spark plug looks fine, actually.
Simon Barber, April 2007
I had the same problem with mine and thought it was fuel starvation but it wasn't a new spark plug cured the problem
Paul R, April 2007
I had this problem with a couple of petrol engines and the problem was a spark plug which stopped working when it got heated, replacing them worked for me
