As per my recent thread in the "Technical" section of this website my six month old Honda EU20i generator recently developed a fault which caused it to run roughly and then cut out. Sometimes it would run for a couple of hours without issue and other times only a few minutes.
A warranty investigation and repair strongly suggests the issue is the faulty manufacture of the spark plug cap. Apparently this is a known issue and is a simple and quick fix for the Honda dealer ie. they fit a new plug cap. Honda service bulletin #56 applies.
Three models are affected (I think these have all been manufactured in the past 18 months):
Model number -- Serial number range
EU1000iT1 - EAAT-1066829 to EAAT-1102783
EU2000iT1 - EACT-1623182 to EACT-1845559
EB2000iT1 - EAET-1009698 to EAET-1012829
This will not always be an easy problem for, especially, non technical owners to identify and, in my opinion, Honda should have issued a recall for the matter - the fact that they didn't for what is generally considered to be the top of the line, and certainly the most expensive, generator in its class is disappointing.
My generator is now running noticeably more smoothly.
An image copy of the service bulletin is attached to this post.
Thank you Mike for posting this information. I thought there was something wrong with mine so I was not surprised to find my serial number was an affected model. I took this info to a Honda dealer who replaced the faulty cap under warranty.