I have a Honda HRA214 SX lawnmower which does not start. No matter how many times I try.

Air filter is good and spark plug is new. I think it's getting fuel as I can definitely smell it.

I attached a neon lamp ignition tester between the ignition cable and the spark plug and it does not light up when I try to start the mower. If I ground the tester directly, bypassing the spark plug, it produces bright light. So it seems that the ignition system does not produce enough voltage for a spark.

It had this exactly same problem a year ago. A couple of months later, when I investigated it, it started normally.

My hypothesis is that the ignition unit has moisture inside due to failing seals or insulation. This prevents it from operating normally. During the warm summer months, the moisture slowly goes away.

So I think that the ignition unit should be replaced. Or does anyone know any other possible reasons for this sort of problem?