Once upon a time on usenet timo wrote:
Hi..sorry to ask.. first post!.. I have inherited a Hayter 56 mower
with Briggs and Stratton which has been brilliant, but the throttle
control doesnt work, only runs at one speed.
I dismantled and cleaned the mower today and its really helped..lots
of loose/ missing bolts, etc.. but I cant work out what is meant to
happen with the springs, are there meant to be 2? I have looked
everywhere on google but none of the engines seem to match the
throttle layout I have? I have replaced the govenor spring with a new
one but that didnt help. The throttle control at the front of the
mower moves, but this doesnt move the throttle control at the end of
the govenor spring, should there be a second spring? I can manually
move the second control and this alters the rev, so no valve issues
(?), but not sure what is mean to move the control?
I've attached some photos so I hope that help? Many thanks and
apologies if Im too vague... its an old machine so no silver plate
with serial nos, etc.. and clearly no expert!.. thanks

I don't know what the problem is. Mower engines are supposed to run at a set
rpm, where they and the blade system is most efficient. The governor is
there to open the throttle more if the revs drop (due to load, long grass
etc.) so as to keep the engine at the optimum speed. If you want to vary the
engine speed (pointless on a mower) then you need to disable the governor.

The 'throttle control' is only there to stop the engine when you're done.
Some mowers can be set to idle but there's really no point - you either want
the thing running (and working) or not. On or off.

I know of instances where it has been decided that the mower runs too fast
as they grass is only short so they've been slowed down by modifications.
Usually the engines don't last long as they're designed as a single-speed
unit and running them at lower speeds means insufficient cooling from the
engine-driven fan / inadequate oiling / non-clean fuel burning and
out-of-spec forces on critical components when the load does vary.
--
Shaun.

"Humans will have advanced a long, long way when religious belief has a cozy
little classification in the DSM*."
David Melville (in r.a.s.f1)
(*Diagnostic and Statistical Manual of Mental Disorders)