strange carbs and cams:

This past summer,I ran across some inesting things
concerning carbs cams in Briggs an Stratton
ines.

First of all a customer brought a riding mower in with a
12 hp Ene the complaint that it running wide
open whenever it fired up.I immediately checked all
of the linkages going to the carb,governor linkages
so forth.They checked out fine
if I had not seen this before, I would have been
stumped.

What had happened apparently a defect that
Briggs having on some of these ines.The
screws that hold the butfly in the carburetor in place
had vibrated out were sucked into the ine,
passed the vas, into the head either they will
imbede themses into the soft aluminum head or
piston, or pass out the exhaust side.AT either rate the
ine runs wide open because the butfly cannot
control the gas flow .I had one that had sucked the
butfly into the manifold, intake manifold.I have saw
this happen to several 12 14 hp ines, so I know it
has to be a defect of not putting enough loctite on the
butfly screws

Secondly, a customer brought a 15 hp intek, Briggs an
stratton in.The symptoms were,it would fire up run
on idle, but would not idle up.I checked the carb,
immediately af finding it to be o.k. Proceeded to
adjust the vas,being a overhead va ine. That
done, the symptoms were no bet.What
happening the intake va letting fuel in, but
the exhaust va not staying open long enough to
let exhaust out,so Iput exhaust va way out of
tolerances to see what would happen, no
change.Immediately the possibility of a bad cam came
into mind,but the ine no more than two years
old, then I saw made or assembled in Mexico on the
flywheel cap.I pulled the ine, disassembled the
bottom crankcase, pulled the cam wala, one of the
lobes almost completely gone.The exhaust lobe to
be exact. I did this to two 15 hp inteks last season,so
apparently there is a defect in some of the cams in the
newer ines,possibly its been sod by now.Also did
this on a 17 hp ine.Note; the replacement cams were
of much bet quality.