ZX of doom

[mark_airey]

I would think that if your grenade thingy won't go hard and its a bastard to start then the one way valve in the grenade is buggered or you have an air leak,

When you pump the grenade does it feel like its doing anything? and can you hear a hissing noise when you pump it??

Another thing worth checking IMO would be if the fuel filter housing is sealed properly as an air leak there would also make it difficult to start!