Ignition coil?

[maxtorman1234]

While trying to start my 310 for about the fourth time i had forgot that i checked the spark plug the other night and forgot to reconnect it. I didnt realize the spark plug was not connected and now it wont start. Could it be the ignition coil? The warning sticker says that if i disconnect it while it is running it could cause permanant damage to the ignition coil. Isn't trying to start it disconnected and disconnecting it while running basically the same thing? THanks

[UCD]

First be sure that you did not flood it. Take the plug out and see if it is wet. If it is dry it with a lighter or match. Clear the cylinder by opening the throttle wide open and with plug out crank it over a few times. reinstall the plug and plug wire and try to start in your normal way. I don't think cranking it with it disconnected would be the same as disconnecting it while it was running

[torinwalker]

I got this great article from Briggs and Stratton on weak spark. Perhaps the moderator would do us a kind favour and publish it somewhere in the FAQ section so it won't be lost? Knowing what I know about basic transformers, I doubt very much you'd damage a coil by disconnecting it. (But I could be wrong.) Also check for carbon (excellent explanation of good spark below). Your plug could be grounding through the build-up. Pasting now: Let's look at what is required to create a good spark. Flywheel: The flywheel magnet must generate a sufficient magnetic field to start the chain of events in motion. A fair test is to hold the flywheel on edge with the magnet facing up. Place the blade of a 10" #3 (1/4") straight blade screw driver against the magnet. Release the screwdriver. The magnet should have enough strength to hold the screwdriver straight out. If we pass this test, assume the magnet is OK. Rotational speed: Remember speed is a factor. The engine must be pulled over at a minimum speed of 250 RPM before the coil will even think about firing. Thick oil on a winter day or a heavy parasitic load may cause problems. Customers come into play here as well. Shorter or elderly individuals may not have the leverage or strength required to reach the RPM necessary to activate the Magnetron's electronics. Spark Plug: The spark plug is a major element of the equation. A new spark plug may require around 10,000 volts to jump a .030" gap when the engine is cold. This drops to just 4,000 when the engine is hot as electrons are more easily emitted from a hot surface. That's one of the reasons the old vacuum tubes in radios had to warm up before the radio would work. Electrons are also more easily emitted from a sharp edge than a round one. A spark plug begins to require more and more voltage as normal wear causes the edge of the center electrode to become less defined. And finally, an internal short or carbon/oil fouled plug simply shunts the high voltage burst straight to ground, resulting in insufficient spark or no spark at all. Ignition Coil: The ignition coil is probably the easiest thing to check and therefore the first thing to check when embarking upon ignition system troubleshooting. Install the Briggs & Stratton spark tester, part number 19368, between the high tension lead and a good engine ground. Spin the engine over (at least 250 RPM) and watch for spark in the tester window. As simple as it seems, this is a fairly comprehensive test. The tester electrode gap is .166" wide. Those wise in the way of electrons have calculated that it takes around 13,000 volts to jump this gap. We need 10,000 to jump the gap on a cold spark plug. Add it all up and we have voltage to spare. Engine quits while running? Hook the tester up in line with the spark plug and start the engine. When the engine quits, monitor the window. If spark is present, the problem is not in your ignition coil. By the way, this test stresses the coil well beyond the demand it would see in operation. Think about it. We're asking the coil to build enough voltage to jump TWO gaps - the tester as well as the plug. If your engine starts and runs OK cold and hot, you've got a healthy ignition coil. Note: because Magnetron Ignition coils depend on the flywheel magnets to operate, they will function even if the flywheel key is sheared - unlike breaker point systems. One additional test you can perform: check the impedance (resistance) of the secondary circuit at room temperature. Hook an ohmmeter test lead to the spark plug terminal of the high tension lead and another to the lamination stack (ground). Your resistance reading should range between 2,500 and 5,000 ohms. If infinite (no continuity), an internal open circuit exists. Replace the coil. If infinite but the engine runs, your problem is an internal break of the high tension lead, a poor attachment of the spark plug terminal or improper mating of the high tension lead to the coil. A pin within the coil body, skewers the lead. If the pin does not contact the wire core, there will be no continuity. The coil will often have enough available voltage to jump the gap, so you see spark. The internal arcing that occurs within the high tension lead will eventually create enough resistance that ignition system performance will suffer. If your resistance reading is much lower than 2,500 ohms, an internal short exists. Replace the coil.

[maxtorman1234]

Thanks you guys but mine is brekerless and i have tracked it down to the "trigger module" the coil is ok. Does anybody know what a "trigger module" would cost to replace? Thanks

[EDS]

I would like to know how you know it is the trigger coil. Is the coil open or does it have some resintence?

[ka9bxg]

If you find one please let me know since I also have one that is bad and need one. Thanks Bob

[maxtorman1234]

EDS, the trigger is open all the time. I phoned Kohler and it costs $200 Canadian[V] for the trigger module. I could probably get a whole engine for under 300!!. If anyone has one please let me know. Thanks