My 5 year old Honda mower has had trouble getting going in the spring — despite my totally running the carb dry in the fall.

In the spring, it runs for about a minute, then coughs and backfires and quits... unless I'm quick on the gas and can get it back on-track. Basically, I can cut 4 or 5 paces before the konk-out.

I ran fuel cleaner through the tank and lubed all moving throttle parts. Nothing worked.

Finally, I took out the plug and found it totally sooty, with a clean spot where the spark was happening. The gap was good and there was nothing obviously wrong with the plug. Over 5 years, it had maybe 100-150 hours of work.

So, I splurged and bought a $5.00 NGK plug, the same as was in there from the factory.

Instant success! I pulled the new plug after cutting the back lawn and it was so clean that I could have taken it back to the store!

I put the old plug back in and the old problems came back.

Lesson: check the plug, even if the symptoms seem to be from other causes.