Hi, recently I made the mistake of turning my mountfield on it's side to clear a trapped piece of wood underneath. Now the mower keeps revving and up and down. Have removed spark plug and cleaned it, it was covered in black soot. How does the choke work. could it be open full.

simon, June 2008

change 470 blade boss holder

steve, May 2013

broken blade boss holder

steve, May 2013

any other queries about this particular mower are welcome to be emailed to me, as like i previously said i have recently rebuilt one which was bought cheap as scrap and fully rebuit email any queries to chris at chrisblaylock "AT" hotmail .co .uk and i will answer as soon as possible which is usually within 24 hours.

CYBORG, September 2010

the parts for this particular mower are fairly common on ebay, and as i have just rebuilt one of these i would say check your govenor springs, air filter and as for the diaphram gasket , turning the mower on its side should not affect it how ever it is worth noting that if your going to do repairs that require tipping this mower up or over it is a wise move to drain the oil and fuel as with this particular mower it causes problems.
Also the choke is located inside the carb tube and is a automatic choke hence the reason for the mower to have the two govening springs on it. and spark plugs usually are relitavely sooty.

CYBORG, September 2010

I had the same problem. I turned the mower on its side (petrol tank uppermost - it was empty though). I've cleaned the air filter and have replaced the spark plug. Still having problems though.

Rob P, June 2010

Where do you get the diaphram from & what model No is the engine??

111, May 2010

how to clean out the carburetor on a Hp470 as mine keeps onm cutting out.

Ian MIddlehurst, March 2010

i got the same problem and was told it could be diaphragm in carb .......

ben, August 2008

Hi I had the same problem when I turned mine over to do a repair. The problem was caused by the the air filter getting clogged with oil. It was a simple job to unscrew it and I just cleaned it out with meths.

John, June 2008