At the base of the engine you will see 4 holes that are roughly 2.75 inches equally apart. The clutch points straight down as you mount the engine directly on top of the leg with the pull cord facing toward the front of the kayak. Make sure the engine is either on your boat mount or a saw horse to ensure and easier fittment. You start the 4 stainless bolts from underneath engine going through the clutch housing and into the base of the engine. Gently snug them for the moment and slowly tighten around the base until they are firmly tight, but not to tights as this is aluminum.
You are to gently tie wrap the throttle cable down the control arm until it bends upward to connect into the carburetor. You need to remove the air filter cover and you will see the throttle lever. At the end of the throttle cable loosen the screw and test fit the cable end into the throttle plate. You will see the cable end seats into the grove and pulls into the tapered opening end of the throttle plate. Pull downward and wrap the end of the threaded shaft in the engine bracket that you see in the picture. Now, before you tighten anything up, spray lubricant down the cable sheath and apply a bit of marine grease on the opening of the cable at the ends of both sides of the cable. This keeps moisture at bay. Tighten the adjustment and tie wraps and test the throttle opening and closing with the grip shifter.
The switch enables the CDI ignition to ground and turn off the spark to the spark plug. You will need to cut the connector off of the wire set coming out the tube. Then the first step is to pick one wire from the two that exits out of the tube covering and splice this into the engine wire that exits behind the carburetor. A water proof male/female quick connector works or a butt connector. If you want to remove this later, use a proper connector. The second wire needs to be ground to one of the base bolts on the clutch housing. I would use a stainless ring connector for this. Make sure the red kill switch cover is pressed into the switch and proceed to fill with gas, prime the ball, and close the choke until it sputters when starting. 4 strokes start with little effort.
Depending on which way you mount the arm, the numbers for throttle position could be opposite. Normally this does not bother me, but you want to make sure the throttle starts on idle and climbs progressively to max rpm and full throttle. Most Honda engines will max before they reach the end throttle position, when you twist the grip. Remember the adjustment on the carburetor, if you need have a better idle or max throttle position.