snowhound 105 #1 Posted May 23, 2022 When I turn off my 416 K series it trys to keep running would that be caused by running to rich or to lean? 2 Share this post Link to post Share on other sites
kpinnc 12,083 #2 Posted May 23, 2022 I'd check the energizer lead on the coil. When switched off, you should have zero volts on the negative terminal on the coil. Only other thing I can think of is carbon build up on the head may be cooking off. Do you idle down before shutting off? I have no choice because I have canister mufflers and don't want a backfire. 3 Share this post Link to post Share on other sites
Handy Don 12,235 #3 Posted May 23, 2022 43 minutes ago, snowhound said: When I turn off my 416 K series it trys to keep running would that be caused by running to rich or to lean? It isn't necessarily either rich or lean, it's that fuel and a means of ignition are still present in the cylinder. Turning off the power to the coil (or grounding a magneto) does not stop the flow of fuel into most WH engines through the carburetor. It only stops sparking at the spark plug. Carbon buildup in the cylinder, is one potential cause for "run on" if it is hot enough to cause fuel to burn. Poor quality, low octane fuel can also be a source of "dieseling". Backfiring at shutoff comes from fuel not burned in the engine coming into contact with a hot muffler (and can be damaging to the muffler). All that being said, are you sure it's really switched off? As @kpinnc notes, there should be no power at the coil when the ignition switch is off. A bad ignition switch (or a short?) could be keeping it powered. 3 Share this post Link to post Share on other sites
kpinnc 12,083 #4 Posted May 23, 2022 1 minute ago, Handy Don said: A bad ignition switch (or a short?) could be keeping it powered My thoughts exactly. Number one cause of all electrical problems is the keyswitch itself. 2 Share this post Link to post Share on other sites
953 nut 55,297 #5 Posted May 24, 2022 Probably the build up of carbon in your engine's cylinder and the idle speed setting being a bit too high. If you bring the engine to a low idle a couple of seconds before turning off the ignition switch it should help. I doubt that the problem is in the ignition switch because their failure mode is generally open (no voltage being passed). 1 Share this post Link to post Share on other sites
