posted 03-23-2014 01:04 PM ET (US)        

I started the motor today and it ran nicely for ten minutes, then began to run roughly. I pulled on plug and it looks black and slightly sooty.

So I imagine [the cause of the rough running] is either a fuel [problem] or a spark [problem].

Can I successfully clean the spark plugs? If so, what is a good method? The plugs are NGK Iridium plugs, if this makes any difference.

My local auto part store does not have the NGK IZFR5G, but has an Autolite equivalent. Would it be a bad idea to use a generic replacement?

What would a good method to clean the injectors?

posted 03-23-2014 01:56 PM ET (US)            

At the price of six new iridium spark plugs, I would not replace them until I was certain that the problem of plug fouling is remedied. I'd just clean up the original plugs, and put them back into use.

I do not think that by spraying a fogging oil into the air intake that you could have caused any clogging of the fuel injectors. The fuel to the fuel injections is provided by a separate path, not via the air intake, and there is positive pressure at the injectors that sprays their fuel into the combustion chamber. I don't think some fogging oil could clog those injectors.

You can clean soot from spark plugs with any sort of solvent and some air blast.

Try to get the engine running again. Perhaps you can brew up a small batch of gasoline that has been treated with a fuel system cleaner--something like Mercury's QuicKleen additive in a high concentration--and run a gallon or two through the engine.