I ordered a set of these Accu Spark inline testers from Britain and as soon as they arrive, I’ll post a report on them.
Here they are in action being used by fellow outboarder kodibass on a ten horse Johnson. If you don’t want to watch the whole video, he has good shots of them at 1:04 and 12;41 in this video.
Another trick is to just use an old cylinder head with the good plugs screwed into it. It can either be bolted to the block or grounded by using a short piece of wire with an alligator clip on the end. This way you can see all two, four, or six ignition systems firing at once.
