Adjustable throttle linkage for outboard motors

An adjustable throttle linkage for use in an outboard motor having a pivotable throttle valve, and a throttle lever for controlling the position of the throttle valve. The adjustable throttle linkage comprises a connecting link having opposite ends, one end being connected to the throttle lever. The other end of the connecting link is adjustably connected to a control member in turn connected to the throttle valve. The apparatus for adjustably connecting includes a yoke connected to the control member, and the yoke includes a body having a first portion including a central bore adapted to house the threaded portion of the connecting link. The yoke includes a slot including opposed surfaces and housing a thumb wheel, the thumb wheel being threaded onto the threaded portion of the connecting link such that threaded movement of the thumb wheel on the connecting link causes movement of the yoke with respect to the connecting link.

FIELD OF THE INVENTION 
The invention relates to internal combustion engines and outboard motors, 
and more particularly, to throttle linkages and means for adjusting 
throttle linkages. 
BACKGROUND OF THE INVENTION 
Attention is directed to the Donohue U.S. patent application Ser. No. 
635,172, filed July 27, 1984 now U.S. Pat. No. 4,602,602 and assigned to 
the assignee of the present application. That patent application 
illustrates a throttle control linkage for use in an outboard motor, the 
throttle control linkage including a bolt or link connected to a throttle 
lever and a connecting member threaded onto the bolt and providing a means 
for connecting the bolt to a cam. The cam is in turn functional to control 
the position of a throttle valve of a carburetor. The connecting member 
includes a central threaded bore such that it can be threaded onto the 
bolt or link. Adjustment of the relative position of the throttle lever 
and the cam is achieved by disconnecting the bolt or link from the 
throttle lever and then rotating the link in the threaded bore of the 
connecting member. The link is then reattached to the throttle lever. 
Attention is also directed to the Frahm U.S. Pat. No. 4,071,002, issued 
Jan. 31, 1978; the May U.S. Pat. No. 3,234,924, issued Feb. 15, 1966; the 
Fletcher U.S. Pat. No. 2,968,192, issued Jan. 17, 1961; the Morse U.S. 
Pat. No. 2,702,615 issued Feb. 22, 1955; and the Boyce U.S. Pat. No. 
2,103,348, issued Dec. 28, 1937. 
Attention is further directed to the Maxant U.S. Pat. No. 2,653,663, issued 
Sept. 29, 1953; the Coots U.S. Pat. No. 2,600,852, issued June 17, 1952; 
the Garson U.S. Pat. No. 2,561,440, issued July 24, 1951 and the Spiller 
U.S. Pat. No. 2,451,636, issued Oct. 19, 1948. Attention is further 
directed to the Sargent U.S. Pat. No. 1,523,142; the Warrener U.S. Pat. 
No. 1,329,645, issued Feb. 3, 1920; the Mills U.S. Pat. No. 1,102,782, 
issued July 7, 1914; the Connelly U.S. Pat. No. 842,770, issued Jan. 29, 
1907 and the Siegel U.S. Pat. No. 3,078,738, issued Feb. 26, 1963. 
SUMMARY OF THE INVENTION 
The invention comprises an adjustable throttle linkage for use in 
controlling operation of an internal combustion engine having a carburetor 
including a pivotable throttle valve, a throttle valve position control 
member operably connected to the throttle valve and movable so as to 
control the position of the throttle valve, and a throttle control lever 
for controlling the position of the throttle valve. The adjustable 
throttle linkage includes a connecting link having opposite ends, one of 
the opposite ends being connected to one of the throttle control lever and 
the throttle valve position control member. Means are further provided for 
adjustably connecting the other of the opposite ends of the connecting 
link to the other of the throttle control lever and the throttle valve 
position control member, the means for adjustably connecting including 
means for adjusting the position of the throttle lever with respect to the 
throttle valve position control member while the throttle lever and the 
throttle valve position control member are joined by the connecting link. 
The invention also includes an outboard motor having a throttle valve 
supported for pivotal movement between a throttle open position and a 
throttle closed position, means for controlling the position of the 
throttle valve including a movable member connected to the throttle valve 
for causing movement of the throttle valve, a throttle lever supported for 
pivotal movement, and means for connecting the throttle lever to the 
movable member. The means for connecting includes a connecting link having 
opposite ends, one of the opposite ends being connected to one of the 
throttle lever and the movable member, and a second portion of the 
connecting link being threaded. Means are also provided for adjustably 
connecting the second portion of the connecting link to the other of the 
movable member and the throttle lever, the means for adjustably connecting 
including adjustment means for adjusting the position of the throttle 
lever with respect to the movable member while the throttle lever and the 
movable member are joined by the connecting link. 
In one embodiment of the invention the means for adjustably connecting 
comprises a yoke connected to the other of the throttle valve position 
control member and the throttle lever, the yoke including a body having a 
first portion including a central bore adapted to house the threaded 
portion of the connecting link. The first portion of the yoke includes a 
slot including opposed surfaces. An adjustment member is housed in the 
slot and has a central threaded bore. The adjustment member is threaded 
onto the threaded portion of the connecting link, and the adjustment 
member has opposed faces, one of the faces engageable with one of the 
opposed surfaces of the slot and the other of the faces of the adjustment 
member is engageable with the other of the opposed surfaces of the slot 
such that threaded movement of the adjustment member on the connecting 
link causes movement of the yoke with respect to the connecting link. 
Various other features and advantages of the invention will be apparent 
from the following description of a preferred embodiment, from the claims 
and from the drawings.

Before describing at least one embodiment of the invention in detail, it is 
to be understood that the invention is not limited in its application to 
the details of construction and to the arrangement of the components set 
forth in the following description or illustrated in the drawings. The 
invention is capable of other embodiments and of being practiced and 
carried out in various ways. Also, it is to be understood that the 
phraseology and terminology employed herein is for the purpose of 
description and should not be regarded as limiting. 
DESCRIPTION OF A PREFERRED EMBODIMENT 
Illustrated in FIG. 1 is an outboard motor 10 including an internal 
combustion engine 12. The engine 12 includes a carburetor having a throat 
14 housing a pivotable throttle valve 16 for controlling the flow of the 
fuel mixture through the carburetor throat 14. The engine 12 also includes 
a throttle arm or lever 18 supported for pivotal movement about a central 
pivot 20. 
Means are also provided for connecting the throttle lever 18 to the 
throttle valve 16 such that pivotal movement of the throttle lever 18 
about the central pivot 20 will cause consequent pivotal movement of the 
throttle valve 16 about its central pivot axis and to thereby control the 
position of the throttle valve 16. While various means could be provided 
for connecting the throttle lever 18 to the throttle valve 16, in the 
illustrated arrangement, the apparatus includes a cam 24 supported for 
pivotal movement about a pivot shaft 26 and connected to the throttle 
lever 18. The cam 24 is caused to pivot about the pivot shaft 26 in 
response to movement of the throttle lever 18. A second cam 28 is 
supported for pivotal movement about a parallel pivot shaft 30 and the 
second cam 28 includes a roller 32 adapted to engage a cam surface 34 of 
the first cam 16. A linkage 36 is pivotally connected at one of its ends 
to the second cam 28 and is pivotally connected at an opposite end to a 
lever 38 supporting the throttle valve 16. 
In a preferred form of the invention, a spring 40 is connected to the lever 
38 and biases the lever 38 and throttle valve 16 toward the fuel flow 
restricting position shown in FIG. 1. When the throttle lever 18 is 
pivoted in a clockwise direction as shown in FIG. 1, the first cam 24 will 
be caused to pivot in a clockwise direction around the pivot shaft 26. The 
cam surface 34 engaging the roller 32 will then cause counter-clockwise 
rotation of the cam 28, and the linkage 36 connected to the cam 28 will 
cause pivotal movement of the throttle valve 16 to a throttle open 
position. 
Means are also provided for connecting the throttle lever 18 to the first 
cam 24 such that the relative position of the throttle lever 18 and first 
cam 24 can be adjusted with respect to one another and without 
disconnection of the throttle lever 18 from the cam 24. The means for 
adjustably connecting the throttle lever 18 to the cam 24 includes a 
connecting link 50 having one end 51 pivotally connected by a pivot pin 53 
to the throttle lever 18. The opposite end of the connecting link 
comprises a threaded shaft 52. Means are also provided for pivotally 
connecting the threaded end 52 of the link 50 to the cam 24. This means 
includes a yoke 54 pivotally connected to the cam 24 by a pin 56, the pin 
56 being spaced from the pivot pin 26 supporting the cam 24. The yoke 54 
also includes a bore 58 extending perpendicularly to the longitudinal axis 
of the pin 56 and being adapted to house the threaded shaft portion 52 of 
the link 50. The bore 58 is larger in diameter than the threaded shaft 
portion 52 of the link 50 such that the threaded shaft portion 52 of the 
link 50 is slideably movable in the bore 58 in the direction of the 
longitudinal axis of the bore. The yoke 54 also includes a slot or space 
60 adapted to house a thumb wheel 62 threadably supported on the threaded 
shaft portion 52 of the link 50. The thumb wheel 62 includes a central 
threaded bore housing the threaded shaft 52 such that rotation of the 
thumb wheel 62 on the shaft 52 causes adjustable movement of the thumb 
wheel along the length of the shaft 50. The thumb wheel 62 also includes 
opposed faces 64 and is housed between opposed faces 66 of the slot. As 
the thumb wheel 62 is rotated on the threaded shaft 52, the face 64 of the 
thumb wheel 62 will engage the opposed face 66 of the slot. Similarly, the 
other face of the thumb wheel will engage an opposed face of the slot. 
Stated alternatively, the yoke includes a pair of spaced apart members 
housing the thumb wheel therebetween in confined relation and such that 
movement of the thumb wheel 62 along the threaded shaft will cause the 
thumb wheel to engage one or the other of the members to cause movement of 
the yoke. 
Such rotation of the thumb wheel 62 will cause movement of the yoke 54 
along the length of the threaded shaft portion of the link 50, and 
adjustment of the relative position of the cam 24 with respect to the 
throttle lever 18 and consequent adjustment of the position of the 
throttle valve 16 with respect to the throttle lever 18. 
In a preferred form of the invention, means are also provided for 
selectively locking the yoke 54 in place on the link 50 i.e., for limiting 
movement of the link 50 relative to the yoke 54. While other means could 
be provided, in the illustrated construction, the means for locking can 
include a jam nut 70 threaded onto the end of the threaded shaft portion 
52 of the link 50 and engaging the yoke 54. 
Using the apparatus of the invention, adjustment of the position of the 
throttle lever with respect to the position of the throttle valve can be 
accomplished without disconnection of the parts providing connection of 
the throttle lever and throttle valve. This eliminates the possibility of 
loss of parts during the adjustment process and also permits adjustment of 
the throttle valve position with a substantial savings of time. 
Additionally, by providing for adjustment with the unit when it is 
assembled, guesswork involved in adjusting the position of the throttle 
valve is minimized. Furthermore, the thumb wheel can be rotated only a 
portion of a revolution and thus the relative position of the throttle 
valve and throttle lever can be accurately controlled. 
Various features of the invention are set forth in the following claims.