Plug reading useless

Bewy said
I think I know what the OP meant, but a blanket statement like he made doesn't cover it.
Really hard to get a read on the colour of the plug electrodes these days with all the different fuels around. But if the plugs are black, you know you have a problem, so removing plugs to check is not a wasted effort.

That's very true, but initial and total timing marks are still a constant regardless of fuel, as they rely on heat.

The key to reading plugs is, knowing WHEN and WHAT to read. In other words, if you read plugs that have been idling for 20 minutes, you're gonna see RICH plugs. LOL