Johnson 33HP Super Seahorse

[Paul Moir]

Re: Johnson 33HP Super Seahorse

Yeah, that's for gapping spark plugs. Which is not what we're doing here. When you do this test, the spark plugs are sitting on the work bench. (or more likely in the lower pan! )

The thing I'm talking about looks like this:

Of course, it can be replaced by the alternative method of banging two nails into a board. The idea here is to force the spark to jump a gap that's wider then normal, which simulates firing under compression.

 

[Xandre]

Re: Johnson 33HP Super Seahorse

If I can't get the spark to jump a gap that is larger than normal do I simply replace the spark plugs?

 

[Paul Moir]

Re: Johnson 33HP Super Seahorse

No. The spark plugs are not involved at all in this test.

If the test fails, it suggests an ignition problem. Since all the ignition components are underneath the flywheel, it needs to come off for inspection. It's not a bad idea to learn how to do that anyway, since the points are under there and need periodic adjustment.

Most often the ignition coils are the culprit - the insulation on them cracks as they get old. As a result, since the ignition coils were so common and so often a problem, new ones are fairly cheap.