: Pop wrote:
: > It sounds to me like the carb might need a good degunking.
: > Probably plugged or partially plugged jet/s. Try screwing
: > needle valves in (gently!) and back out a few time,s then put
: > back to where they were and see if it helps. If not, perhaps
: > something's plugged.
: > You did check for a waterlogged/plugged fuel filter,
: > Fuel's getting TO the carb?
: > HTH,
: > PopS
: I'm thinking too that it's gunked somewhere. Fuel _IS_ getting
: carb (if you pull the starter rope gently with the air filter
: you are met by a mist of fuel around the choke valve). Haven't
: with any fuel filters. Is there supposed to be some sort of
: open the choke plate? It's just that I can't see how it opens
: own (vacuum effect???) and that would explain richness symptoms
: the(new) spark plug and exhaust output popping.
Well, -something- should open the choke plate, yeah. Is it
staying closed or partly closed? If so, that's your problem, or
at least one of them. Sometimes it's not obvious what keeps them
open so look closely. There could be a spring disconnected that
holds it in the open position or something real simple like that.
D Matel gave you a great rundown on how to set the idle/hi speed
mixtures, BTW, so I'd keep that handy. It's "standard" stuff but
not always easy to remember and completely foreign to a lot of
people. His method will work 100% if all is right with the carb
A closed or partially closed choke though will certainly make an
engine run rough or not at all by starving it for air. I suspect
you've come upon the problem if you're relating it correctly.
Your original post has been snipped out so I don't recall the
original details, but it's fairly UNcommon in my experience for a
small engine, esp a B&S, to operate on vacuum. At least I've
never seen one; if I'm wrong, someone will be along quickly to
correct me, I'm sure <g>.
If there is no seperate cable to close the choke, which there
probably isn't on that small an engine, it may be controlled by a
centrifugal force wire when the engine is running and the
positon of the throttle. I never thought much about it because
it's always seemed "obvious" to me when I looked at them, but
darned if I can explain it very well right now.
Maybe Mr. Martel will come back and explain; something tells
me he knows what he's talking about. Or he had a manual handy
If you don't get anywhere and no one offers furhter
assistance, come on back after you study the choke/throttle
linkages a bit and I'll go see exactly what my B&S engines do;
have three of them.
I will say this: When you're assessing the choke plate
position, do so while the engine is running (or trying to). I do
recall that the choke plate on my push mower is mostly closed
when it's at rest, which is fine with me: Keeps the spiders out
over the winter!
HTH a little at least