"Kevin,
The first step is t
"Kevin,
The first step is to set the timing at idle. If the carbs and throttle linkage are set up properly, the throttle plates will be closed when the throttle handle is in neutral.
The idle speed (rpms) is set by adjusting the timing. Advancing the timing will cause the rpms to increase; retarding the timing will slow it down. To change the timing you will have to undo the throttle and shift cables so that you can screw the plastic grommet in the direction that you need. There is a stop screw at the lower end of the timing arm. You wan't to set this screw so that when the screw touches the stop on the side of the engine, the idle speed is in the proper range. Then you adjust the cable length by turning the grommet, so that when the throttle handle is in neutral, the idle stop screw is touching the stop.
If the engine is running properly, the timing is going to be pretty close to zero degrees at idle. The only way you can check this is with a timing light. I don't know of a way to check this statically on the type of ignition system that you have. The timing is determined by a sensor coil under the flywheel, not by a set of breaker points. Maybe someone else knows of a technique for doing this, but I really would not worry about it.
Lets assume that after you set the idle, the timing is close to zero degrees. Put the throttle handle in neutral. The flywheel should have a grid that goes from -10 to + 30, indicating degrees of advance or retard. Turn the flywheel clockwise by hand until the zero degree mark lines up with the arm that is connected to the sensor coil. Now advance the throttle lever to the full throttle position. You can see how much advance you have by noting how the position of the sensor coil has changed with respect to the flywheel. Set the advance stop screw on the upper end of the timing arm so that the maximum advance is about twenty degrees. Since you don't really know that the timing started at zero it is best to settle for a little bit less advance here. You can experiment later if you think that you are not getting top performance, but a few more degrees of advance on a 25 year old engine is not going to make much difference.
If your flywheel does not have a timing grid, you can still use this method. Simply put a mark on the flywheel with a piece of chalk, with the throttle in neutral. Line this mark up with the sensor arm. Open the throttle fully, and put another mark on the flywheel that lines up with the sensor arm. Now you have to determine the angle between thes two marks with a protractor, or some other device for measuring angles. Again, set the maximum advance to about twenty degrees.
Remember that when moving the throttle lever from neutral to forward, you should have someone turn the flywheel clockwise as you move the lever. This is so that the gears mesh in the lower unit. If the gears do not mesh properly, you could damage the shift cable or shift linkage.
This may seem a bit confusing. If you have any trouble with it let us know.
"
