The Oskaloosa herald. (Oskaloosa, Mahaska County, Iowa) 1885-1919, 1915-09-09


What are the relative advantages ana
Disadvantages Of fixed spark as COM
pared with a variable 'sparkf
With the fixed spark ignition occurs
at definite point in the cycle and does
not vary from that point at any time,
and it follows that under certain con-
ditions the best possible results will
not be obtained. For example, at high
speeds the fixed spark may be trifie
too late. However, for small motors
the fixed spark shows excellent results
when everything is taken into consid-
Grafton, such as the elimination of
work on the drivers part in manipulat-
ing the lever and the poor results OBJ
tanned from variable control when the
driver is an unskilled one. s'".fF
Will il injure a casting to lap in a
a piston in a cylinder with carborun-
dum7 ;. -. 80. r. .,- BE-, 81,
The difficulty In using either carbo-
rundum or emery for tapping pistOns
is that the hard abrasive material I'm
beds itself in the soft cast iron so firm
ly that it cannot be removed.
Can you tell me what makes my en-
CINE kick back when starting on the
magnetic? .tH ,r>r.
The reason the engine Kicks back
when starting ON the magnetic is that
the spark is advanced too far This
permits the explosion to take place
before the piston has reached up
per dead center, with the result that
the crank shaft is thrown backward
instead of ahead, and the kick results.
The fault is that you have not retard.
ed the spark sufficiently on the quad
rant, or If you have done this the mag
neto is mistimed. 'Et
How are the valve settings for high
speed engines determined
These are nearly all determined by ex-
pertrhents what is regarded as good
average timing is first given the motor,
and then variations are tried until
finally the best results are obtained.
The design Of the manifolds and yari-
GUS features exercises influences which
cannot be determined accurately by
mathematical calculation. -" &C.. ~..'
Will four inch tire support nearly
twice the same weight as a three inch
tire at the same pressurep Or will not
a four inch tire hold load at a little
more than one-haH the pressure OF the
three inch? ~ E.
The carrying capacity OF the average
four inch tire is about $50 pounds
when the tires are pumped to eighty
pounds pressure and that Of the three
inch tire 4j0 pounds when the tire Is
pumped to sixty pounds pressure. The
four inch tire is designed to carry not
quite twice the load Of the three inch
casing, but reduction in pressure will
reduce its carrying capacity.
My engine runs nicely in the shop,
but as soon as | take it out the cyIin.
ders start to misfire and have no pow
or; then when release the clutch II
starts to pick up on one, two and three
cylinders, and in a few Seoonds, when
the fourth starts to hit, il races terri
bly,. There is also a continuous drip
from the bottom of the oarburstor
when standing still. What is the mat
ter? ,...
1t is difficult to say where your trou-
BILE Is, but there are many possibilities.
The wiring may be in poor condition
and the insulation rotted, so that short
circuits are developed or the timing
may not be correct. There may be bad
leaks around the valve stems or at the
points where the intake manifold is at
tached to the cylinders. There is also
the likelihood that your magnetic and
carburetor are not in good condition
Make certain that the magnetic gives a
good spark at each plug, that all parts
are In adjustment, all connections tight,
all insulation good and the switch free
from loose parts and short circuits.
The fact that the carburetor drips
shows that the float chamber is flood
ing, due to dirt under the needle valve.
leak in the needle valve, gasoline
logged float or bent float arm. The
first can be cleaned out, the second
means that the valve must be ground
by rotating 1t on its seat after applying
some fine valve grinding paste and the
third by drying the float in an oven
and then shellacking 1t. The leak In the
carburetOr would prevent good ad-
justment from being obtained. and 1t rs
possible that all the trouble lies right
here. The flooding of the carburetor
causes the collection Of liquid fuel In
the manifold so that when the throttle
is opened a rich mixture is formed and
the motor misses. . -
The fact that the motor races when
it does run ON all four cylinders would
Indicate that the clutch was slipping.
due either to too much old or a worn
facing, In the former case an applica-
ton Of fuller's earth should be made,
and In the latter new facing must be
applied. .aa
What is live axle and what is its
advantage over other types?
A live axle is one which Is part in