Mountfield SP534 TR 2006 Lawnmower Trouble

Discussion in 'Landscaping and Outdoors' started by crusoe89, Mar 23, 2014.

  1. crusoe89

    crusoe89 New Member

    Hi,

    I have a Mountfield SP534 TR 2006 lawnmower that is in need of repair. The engine starts fine after a few tries and then just dies. It seemed to be in good working order, with new fuel, oil, clean filter etc. and was always stored indoors.

    I checked all the troubleshooting suggestions in the manual and recently fitted a brand new spark plug based on suggestions I read on numerous forums, but nothing solved the problem. I also had to replace the recoil starter and fuel tank to repair a known fault with the design, and that seemed to work fine.

    I can usually get the mower to start, and on occasion I have been able to mow a small amount of lawn before it just loses power and dies. It has been suggested there may be problems with the carburetor, but I know zip about deconstructing engine parts and I don't want to throw more money at it before knowing what the problem is likely to be.

    Can anyone suggest what the likely cause of this could be and how to fix it? I was forced to buy a new mower, but I'd like to be able to salvage this one too.

    Kind Regards,

    Dianne.
  2. Sean_ork

    Sean_ork Screwfix Select

    find someone with a decent air compressor and get it blown through - flush all the old fuel out with new

    does it have a manual flap choke - closed while starting and for a minute while it warms - then open for normal running - is it fully opening ? - are there any tiny splits in the fuel line ?

    failing that, most independent garden centres will have, or they will know, a small engine service chap - cleaning/resetting the carb is a 30 minutes max task
  3. Phil the Paver

    Phil the Paver Well-Known Member

    which engine has it got, if its a Honda one then it might be worth looking at, if its Briggs & Stratton then i wouldn't bother.
  4. crusoe89

    crusoe89 New Member

    Hey,

    Thanks for the reply. I don't know anyone with an air compressor. I did replace the tank with fresh fuel and it was regularly used and re-filled.

    I don't know anything about chokes. It has a choke handle that advises you start the engine on choke and then move it up after the engine has started to the desired speed. I was always able to start it no matter where the lever was.

    Getting the mower to a repair centre is difficult as I don't have a car, so I was hoping to be able to fix it myself.

    Kind Regards,

    Dianne.
  5. crusoe89

    crusoe89 New Member

    Hey,

    I have no idea, but since it was a B&Q Mountfield that didn't cost the earth, I imagine it's not a Honda!

    I was just hoping there may be an easy fix that I could take care of myself.

    Kind Regards,

    Dianne.
  6. Ray Retired

    Ray Retired Member

    Starts, runs, dies...

    I'd start with the fuel filler cap, sounds like the breather could be blocked.

    Try running it with the cap off.
  7. crusoe89

    crusoe89 New Member

    Hi,

    I think I tried that, and also the fuel tank and cap are brand new, but I will indeed try it again to make sure.

    Thanks.

    Kind Regards,

    Dianne.
  8. Phil the Paver

    Phil the Paver Well-Known Member

    Because you have no idea about engines, it's going to be really hard to try and explain what to try, for instances if I said remove the fuel bowl off the bottom of the carb and give it a good clean out and while your in there check that the float is working proberly in allowing fuel through into the carb at the correct rate, I don't think you would have a clue what I was taking about.

    Where abouts in the country are you.
  9. chippie244

    chippie244 Well-Known Member

    it may be that you are running it with the choke on, that would cause it to stop once the engine was warm.
  10. crusoe89

    crusoe89 New Member

    Hi,

    Yeah, I know. I have read on other forums about taking these components apart, and I did manage to find a diagram of the engine. If it was a case of replacing a part, I could probably manage that, and if there was a good description of what to look for I could at least give it a try. I wanted to know the likelihood that the carb is the problem before I attempt it. I'm in Scotland btw.

    Thanks.

    Kind Regards,

    Dianne.
  11. crusoe89

    crusoe89 New Member

    Hi,

    I'm pretty sure I'm starting and running it correctly and I even checked the manual on it to be sure. It did work fine for around 7 years before this problem. Now I start it up, the engine revs into life, and then just fades out again after a couple of seconds.

    Thanks for the advice.

    Kind Regards,

    Dianne.
  12. Sean_ork

    Sean_ork Screwfix Select

    can you take the air filter off, you might also have to take the housing off as well - you need to be able to see the top of the carb - the intake - these just have a flap choke, which you will be able to see and check if it really is opening again after you've got it up to speed - there'll probably be a separate position for choke, half choke and normal

    if the choke doesn't fully open it will run very rich and die under load
  13. Phil the Paver

    Phil the Paver Well-Known Member

    Your carb need a good clean out, the jets are blocked by the sounds of it restricting fuel flow into the engine, there is also a diaphragm in the carb that may have perished/split.

    The trouble is if you cannot sort it yourself, it would be pointless paying someone to do it for you, because the mower is worth £50/60 at best.​
  14. Devil's Advocate

    Devil's Advocate Well-Known Member

    Crusoe, as said above - almost certainly the carb. Although the carbs on mowers tend to be relatively simple, it's still a 'sensitive' component, so your mower certainly won't run if you mess up (eg tear a gasket, puncture a diaphragm, lose the float needle...!)

    My old mower - which I'd leave outside for days - would get water into the petrol tank which would make it conk out and hard to start. Easy to remove and clean the bowl - if you know where it is...

    Ok, when it conks out, what - exactly - does it sounds like? Does it stops DEAD as tho' switched off? Or slow down, splutter, cough - what?
  15. crusoe89

    crusoe89 New Member

    Hi,

    Thanks, I'll add that to my list of thinks to look at.

    Kind Regards,

    Dianne.
  16. crusoe89

    crusoe89 New Member

    Hi,

    Yes, I think that sounds like the problem. I want to make sure any attempt at repair is cost effective. That's why I was asking; to find out if the problem might be simple or not worth the hassle.

    Thanks for the advice.

    Kins Regards,

    Dianne.
  17. crusoe89

    crusoe89 New Member

    Hi,

    By the sounds of all the advice, it is most likely the carb. I have taken pretty good care of the mower and no water has ever gone near it! Still, it has been used a lot over several years, so I can imagine parts have worn down. Cleaning the bowl sounds possible as I have diagrams of the engine, so that might be my next step if it is a likely solution.

    When I get it started, the engine revs into life and then just loses all power and fades out to nothing. No coughing or spluttering that I recall.

    Thanks.

    Kind Regards,

    Dianne.
  18. Phil the Paver

    Phil the Paver Well-Known Member

    when you fitted the new tank, you haven't kinked the fuel line have you causing a part blockage.
  19. crusoe89

    crusoe89 New Member

    Hey,

    Well, I think I was careful when I fitted the new tank/starter assembly, but I can double check that too. I replaced the tank/starter the summer before last and it worked for the whole season. It was when I attempted mowing the lawn last year that it failed to work.

    Kind Regards,

    Dianne.
  20. Phil the Paver

    Phil the Paver Well-Known Member

    Ok not that then, how long was it sat between last use and now.

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