Ian, fuel is sucked up through the centre piece which the float sits around. It is fairly common for the nut at the bottom of the float chamber and bottom of float chamber to accumalte a deposit of very fine reddish coloured sand like material, this maybe causing a blockage.

Just a thought. If the engine runs by pushing the tickler down it would suggest the float is too high, not too low. Is the needle valve clear? Best of luck.

What engine is it? Villiers/JAP other? I may have a manual if I know which engine it is.

Dovesails. I have no experience of the Howard 350, the reply from Richard P will give you an idea of what a plough and rotavator can do. I use a Trusty two wheel tractor and plough the disadvantage of this machine is it does not have a rotavator attachment. My preffered machine is a SIMAR Rototiller...

Peter, many older engines did not have a plug cap as such, just a simple brass tag on the end of the HT lead which was held on the plug by a nut. This could provide a solution, although any suppression would be lost. Independant Ignition Supplies stock the parts, not cheap though. Good luck.

Have a look at the following link, there is a telephone number, they may be able to help.
http://www.madeinbirmingham.org/clifford.htm
Best of luck.