donald girod wrote:
I have a Briggs lawn mower, solid state ignition. It runs normally
(good power, etc) once it starts, and it starts eventually, BUI...

I have to pull many, many times, and after a while the engine starts to
fire weakly. It will fire weakly 10 or 15 times and die, each time
doing a little better. Finally, it fires weakly, doesn't die quite, and
slowly picks up speed. Then it takes off and runs. It will restart
readily when warm, but if left even 10 minutes, it reverts to the
painful starting. The spark is strong (obviously), and I can see gas
splash up in the carb throat when I take the air cleaner off and pull
the rope. When it does start, it does NOT throw black smoke, as it
would if the carb was seriously loaded up with gas, in fact, it throws
no smoke at all, and I would bet that in fact it has been starving for
gas. Maybe.

I have seen other Briggs engines do this, and I have never figured out
what the problem has been. I have done things like take apart the carb
and put in a carb kit (mainly, new diaphragm gasket or whatever that
thing is called), and sometimes I have "cured" the problem. But if
somebody recognizes this syndrome and can tell me what the most likely
problem is, I would surely appreciate it.


This may seem like an obviousity, but if it's an old engine and there's
no primer bulb, then I'd think there'd be a choke valve on the carb.
Usually those are pushed closed when the engine speed control lever is
moved all the way to it's high speed end.

And, with the choke closed, as soon as the engine startes the speed
control lever should be moved back a bit, so the choke opens.

If I'm correct and the carb has a choke, maybe the speed control cable
has gotten sloppy or out of adjustment, or the choke operating linkage
has fallen off so the choke won't close.

Have a look see, it should be pretty easy to see if there's a choke
butterfly valve near the air inlet on the carb.

I've also seen small engine chokes which are closed by a spring when the
engine isn't running and opened by engine vacuum bled through a small
orifice to a rubber diaphragm which pulls the choke open against the
spring force. The orifice delays the choke's opening for a second or two
after the engine starts.

HTH,

Jeff

--
Jeffry Wisnia
(W1BSV + Brass Rat '57 EE)
"What do you expect from a pig but a grunt?"