On 16 May 2006 02:22:22 -0700, "Cokey" wrote:

Just recieved a call from the suppler and he has confirmed that the
knocking noise is quite normal on start-up and shut-down so panic over!
Cheers
Marc.c

Old motorcycles with big single cylinder 4 stroke engines used a cable
operated valve lifter for starting and stopping. The idea when
starting was to decompress the engine, kick it over and then release
the lifter when it was spinnig over. It was supposed to burst into
life. They were hard to kick over under compression and there was
always the danger of it kicking back. The valve lifter was the only
way of stopping the engine (short of stalling it) because the old
magneto ignition didn't have any kind of switch. The valve lifter
used a make a sort of chuffing noise when operated.
Notice how the newer engines are much easier to pull-start then the
old ones. My Flymo RL400 has a B&S 'EZ-Start' engine which has a
profiled cam for starting, but my old Mountfield Rotovator with a much
earlier and bigger B&S engine has no starting aids at all and needs a
hard pull to get it going. You have to sort of feel the pull first,
like with the old motorbike kick starts, or you can get that nasty
pull back on the cord which is hard on the wrist!
Glad your mind's been put at rest about the noise.