MARVEL
damper and may be used as a guide in assembling control rod to
carburetor, the normal position of slot being horizontal when
heat-control lever on dash is set at "heat on" position
and throttle closed.
The heat control lever (J), (Fig. 3) operates the valve (B) in
the outlet of riser heat jacket simultaneously with the valve (A)
in exhaust pipe and an adjustment by moving dash control lever
to "no heat" may be had to the point where no exhaust
gas passes through the riser jackets, thereby shutting off the
heat.
Gases from exhaust manifold enter at opening (N) (Fig. 3) and pass
through riser jacket, returning to exhaust pipe through outlet
tube (M) to a point below valve (A) in damper body (L).
It will be noted in Fig. 3 that valve (A) is connected by means
of connecting rod (H) to roller (E) operating in slot (D) of cam
(C).
The roller (E) is connected by means of a short, loose jointed,
free, lever, to lever (F) which in turn is attached in fixed position
to throttle shaft (G).
As throttle is opened, valve (A) is also opened due to the roller
(E) at end of connecting rod (H) following the slot (D) in cam
plate (C).
Thus the volume of heat through heat jackets of riser will be lessened
as the engine speed increases, depending upon the position of the
cam (C) con-trolled by lever (J).
By observing Fig. 3, showing the "warm up," or "heat
on" position, owing to action of slot (D) in cam (C) on position
of valve (A), as throttle is opened, it will he seen that valve
(A) is caused to remain practically closed (thus insuring most
heat) until engine has attained a speed of approximately forty
miles per hour, after which in higher speeds it opens automatically
and rapidly to "wide open" thus insuring against back
pressure and overheating.
The valve (B) in riser heat outlet is connected by a lever and
link to the cam (C), the position of which is controlled by the
lever (J) , as stated. In the "warm up" position it will
be noted that this valve (B) is held wide open.
In Fig. 4 showing "normal or medium driving position," owing
to the position of carp (C) having been changed from "warm
up" by the control lever (J) on instrument hoard to half-way
down in slot on "medium," the valve (A) now opens directly
with the opening of the throttle, thus insuring less heat than
in the "warm up" position, but sufficient for normal
driving. It will he noted that valve (B) in this setting is now
partly closed.
The "medium" setting of control lever should be used
as soon as engine is warm and will give the best economy and performance
under normal driving and weather conditions. If weather is raw
and cold, drive with lever (J) further up toward top of slot; if
temperature of air is 90 or above, drive with lever (J) below middle
of slot.
For economy and best engine performance it is essential that driving
be done with control lever (J) as near center, or medium position,
as shown in Fig. 4, as driving and weather conditions permit.
In Fig. 5, showing "heat off" position, owing to the
position of cam (C) being still further changed by the control
lever (J) on instrument board, the valve (A) at closed throttle
position is already open partially, and opens quickly with throttle
to full wide-open position. At the same time it will be noted that
valve (B) has been closed by cam (C), thus insuring in this setting
no heat circulation to the system.
This is the setting used during extremely hot weather or under
certain heavy road conditions when engine appears to lose power
because of too much heat.
Starting
To start engine, set heat control lever (J) to top or "heat
on" position, pull out choke button (above the heat control
lever) all the way. Advance spark lever on steering wheel about
half way, and throttle lever about one quarter way and depress
starter pedal. The moment the engine fires the choke but-ton should
be pushed in to closed and the engine al-lowed to run at fairly
good speed for quarter to half minute.
If engine hesitates, pull out choke button and push back in at
once, the object being to secure momentarily a richer mixture to
assist engine in warming up. Even in zero weather it is not necessary
to run with choker out.
It should be borne in mind that the automatic heating system of
the carburetor makes it entirely unnecessary to drive with choker
pulled out and one of the objects of the heating system is for
this purpose, thereby obviating the common practice of diluting
the oil in the crankcase by using an excess amount of fuel while
engine is warming up.
It should be remembered that the position of the heat lever largely
controls the performance of car. Therefore, where quick acceleration
is desired, drive with heat enough to provide same. For all normal
driving the heat lever may be set half way down the slot to "medium" and
in extremely warns weather below that point or even down to the
bottom of slot or "heat off" position.
Adjustments
No change should be made in the carburetor adjustments until after
an inspection has been made to determine if the trouble is in some
other unit. It should be noted that the vent hole is open in filler
cap of main gasoline tank, that the gasoline lines are clear, that
there is gasoline in the vacuum tank, that there are no leaks at
connections between carburetor and engine, that the ignition system
is in proper condition, and that there is even compression in all
cylinders.
If it is necessary to test adjustment or to make a readjustment,
proceed as follows:
Set air screw (8) (Fig. 1) so that the end is flush with the end
of ratchet set spring.
Turn gasoline adjustment (5) to the right very carefully (loosening
packing nut if necessary) so as not to injure the needle point,
until the valve is closed gently against its seat. Then turn to
the left to bring the notch in the disk handle directly below the
guide post above it.
The notch in disk handle of needle is put in handle after the needle
has been carefully set to correct flow by a flow-meter at the factory,
therefore the notch in handle should register with guide post above
it. This setting of needle valve is absolutely essential to get
the best results.
The object in directing that needle be first turned to right until
closed is to insure against two or more turns open, as from closed
position to notch (usually about one turn) is the normal setting.
This being true it is not necessary to turn needle in to the right
firmly but merely far enough to be sure that when turning back
to the left, to the notch registering with guide post, that the
needle is not more than once around, or one turn from its seat.
Set heat-control lever (J) on dash at "heat-on" or No.
2 position, and leave in this position while making adjustment.
Pull out choker to closed position and start engine in usual manner.
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