How to Use a Timing Light on a Honda

The timing light is designed to locate top dead center on the number 1 cylinder. This is useful for adjusting the timing for the spark plug to fire so that the fuel has enough time to burn during the power stroke of the engine. Since fuel burns at a certain speed, the timing of the spark is essential to regulate the time that it fires relative to the RPM of the Honda's engine. If the spark is introduced at top dead center, the fuel never has enough time to burn completely. When the spark is introduced before top dead center, the fuel begins to burn on the compression stroke while the piston is coming up and enhances compression. This gives more time for fuel burning and increased power. However as the engine RPM increases, the fuel has less and less time during the stroke to burn. It can not burn faster, so the spark has to be advanced to burn earlier in the compression stroke to make up the difference. This is what is determined with the timing light. Use the timing specifications located on a placard under the hood of the vehicle. Different Hondas will differ at idle, depending on their particular compression ratios.

Instructions

1. Locate the specifications for your vehicle. Remove the timing hole cap on the top of the transmission housing. Locate the timing marks so they can be easily identified. There will be a pointer in the middle of the hole, and a line on the flywheel which indicates top dead center. To the left and right of the line will be degree marks to indicate how many degrees before or after top dead center the timing is. The "before" timing mark is what is of interest.

2. Hook up the timing light to the Honda by hooking the spark plug wire clamp around the number 1 cylinder plug wire. This is the one closest to the front of the engine. Hook the alligator clip ends to the battery--red to positive and black to negative.

3. Start the engine and push the button on the timing light that asks what size engine. Push the button until 4 cylinder shows up. Turn the timing knob on the light to 0 degrees. Point the light at the timing hole, and pull the trigger on the timing light. Turn the timing knob slowly until the straight 0-degree line on the flywheel moves up slowly under the pointer. Read the number of degrees that the pointer of the timing knob indicates on the timing light. If the knob shows that it took 18 degrees to move the line on the flywheel to the pointer, then it is 18 degrees before top dead center. If the Honda's specs were 14 degrees before top dead center, the timing is a little too advanced.

4. Loosen the nuts on the distributor that hold it down. Rotate the distributor a very small amount in the same direction of rotation to reduce the spark advance. If the spark advance was lower than required, then rotate the distributor the opposite of its normal direction of rotation.

5. Check the timing again by pointing the light at the timing hole and pulling the trigger and adjusting the knob until the line is under the pointer. Check the amount of advance now. Repeat the process of moving the distributor until the timing is correct. Tighten the nuts on the distributor and remove the timing light.