THE DEAL WITH FLOODED ENGINES + SPARK PLUGS: What can happen when you have determined that a vehicle gets fuel and has spark and just stobbornly doesn't run after many tries and perhaps has been fixed is the spark plugs get soaked.
You may not see this as a litterally wet plug. You can even pull one out and ground it and it will spark?? Hmmm - all the right ingredients but still doesn't taste good?!?!?
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You have already pulled all your hair out, cleaned and dried the plugs, put them all back in and it won't so much as poop for you?!?!? Historically we get a flooded engine and put your foot to the floor which allows for a choke to kick OFF and no extra fuel would go in and it would start with some effort and blow out a black cloud then be fine and on your way. You could also just wait hours perhaps and it would behave.
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This situation has happened to me enough that now I know that some plugs can get so wet they won't dry out without taking them up and get the electrode end hot enough to glow red including the white porcelain insulator. Even that is iffy and new plugs can be easier than that job.
What has happened is that the porcelain is saturated and conducts the spark to ground by itself instead of making an air gap spark so the engine essentially has no spark - but you tested it?? Plugs will spark without pressure far more easily than under pressures as when waiting to fire the fuel mix.
This is faily uncommon but still can happen especially when several tries have been made and perhaps some parts have been replaced and tried and the right problem has been solved and then this happens and you don't know what to do. Most of the time you have fixed the initial problem and this does not happen and a running engine cleans up its own plugs.
I've seen this so bad that you just can't put in new plugs. In that case and if this is really the suspect problem at that point the only thing to do is leave all plugs out for many hours and even if possible air out the cylinders with shop air to dry them. Then the new plugs will behave and the problem is solved.
This is a problem that frequently get to a mechanic and can happen to real mechanics while fixing a problem when there have been many tries to start the engine and it was beyond plain flooded but to an extreme.
We see this more frequently as just one or two plugs that get oil fouled and nothing but a new plug will help. It's an annual thing for me with assorted two stroke engines that sit for an off season or perhaps a year or so like a chainsaw that you haven't needed and so on.
This problem is somewhat rare as I said. The source could have been a wet engine that if it was dry would have worked but then this happens after all has been ruled out. Note that some spark plugs are very resistant to this happening and for the two stroke market Champion is marketing a plug called
"The One Tug Plug" as by nature this happens more to two stroke engines.
Class Dismissed
T
Tom Greenleaf - MetroWest Boston - USA
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http://www.acsource.com/
(This post was edited by Tom Greenleaf on Aug 20, 2007, 4:53 PM)