Random dead miss.

[sgkent]

the first time I came across bad new plugs was in 1972 on the way from Pasadena CA to the SF Bay area. Sports car would start missing climbing grades or under high speed load on I5. I5 was new at the time and very little traffic. The next time was last year watching and listening to people troubleshooting random misfires. It doesn't help that a lot of consumers buy the cheapest plug of known name they can find, and often it is a counterfeit. In the last year I'll bet this has been repeated 20 - 25 times where people are chasing that, "the engine just isn't itself" syndrome. Glad you found it.

SGKent said the other day:

try replacing it with a known good used spark plug since the guy put his own in, unless he will pay for a new one. There are so many counterfeits out there now it is unreal. They can check fine out of the engine, but under compression they can fail.

 

[Auto Doc's]

Boy what a splitting headache I got this morning...Seeing double.

Okay I got a Red mower with a black seat and four wheels.

It is a problem I have never seen before. The engine has what I would call a random dead miss. It came in surging and would not run with the deck engaged. Found water in the fuel system; therefore, the Ruixing carburetor and fuel supply got a full cleaning. Now it has this random dead miss off load and under load. Anyone seen this problem that might point me in the right direction? It either has a loose valve seat or an ignition problem. Hate to pull the head and find nothing wrong but these engines do like to blow the head gasket.

At least the work load is now light as Fall approaches. Boy has it been a year of unique problems...

Oh BTW here is some more info that everyone would ask for. Second sentence was just a joke like we get a lot these type of equipment descriptions here...

Yard Machines 13AN77SS000 SN 1L190B70056 42" cut deck.
Briggs and Stratton 31R907-0062-G1 SN 2002200209498.
And seriously it is a Red mower with a black seat and four wheels.

Have you disconnected to coil kill wire and run it to see if the problem still exists?

Along with what you describe, it may be an ignition coil breaking down.

If it has a Torch plug, I will say throw it away and try a known good plug.