Outboard motor ignition spark plug troubleshooting.
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There are many simple checks you can perform without a lot of test equipment around.
Having a good spark on each cylinder is essential.
It is also extremely important to generate enough spark at the spark plugs to crank your outboard.
You must also have a good battery, a good starter, clean and tight connections are also a must on all but the small Manual start outboards.
On the smaller models you can get someone to help you pull the crank on it while you check the ignition.
Now onto the actuall troubleshooting:
You can get your normal screwdriver with an “insulated” handle and without removing any of the installed plugs, remove the wire from a plug and slide it on the screwdrivers metal end.
Now you will need to remove the remaining plug wires and ground them directly to the block. Using some short pieces of wire is sufficient enough.
Hole the screwdrive safter half an inch from the engine block and away from any moving parts. Do this so that you can observe the park jumping the half gap while you are cranking.
Make sure you are holding the insulated handle while doing this.
Before proceeding you will need to remove the remaining plug wires and ground them directly to the block.
Using some short pieces of wire is perfectly fine.
Grounding the plugs is necessary to prevent the motor from starting up while checking it!
Have your friend at the switch to spin the motor or pull the cord on smaller motors. While your friend is doing this look for a strong spark jumping across the quarter and half gap between screwdriver and the block.
The repeat this for each cylinder one by one.
If you are holding the screwdriver improperly you will feel a really good shock, and this also means that there is a good spark, but we don’t recommend you doing this as it is dangerous.
If there was no spark seen then your next step will be to test the key switch elimination, but that is for another tutorial.
If you only got a spark on some of the cylinders and not all of the cylinder then you will need to check the individual parts that make up the ignition such as coils, power packs, switch boxes, stators and triggers to see if there is a fault with one of those.
We will also be writing a tutorial on testing with ohn-meters on seperate ignition components.
You can always try running your motor with timing lights on the different cylinders and looking at the light. This will sometimes allow you to work out if the miss is ignition or fuel.
For exact specifications and details concerning your particular engine you should refer to a manual for your specific motor.