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(Ignition Kill Circuit)
(J. Reeves)
A Black wire (ground) should lead from the powerhead to the powerpack. There will also be a Black/Yellow wire leading from the powerpack to a raised "M" terminal of the ignition switch. To complete the circuit, there will be a Black wire from the other "M" terminal of the ignition switch to ground.
When the key is in the OFF position = The two "M" terminals are connected,. effectively shorting/killing the ignition.
When the key in ON position = The two "M" terminals are not connected and the ignition is engaged.
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(The lack of a "kill switch" indicates that the ignition is engaged UNLESS the key is ON)
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The mention of "Slow Cranking" was mentioned by "racerone" due to the fact that you DID NOT mention it. We need to know one way or the other.
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(Thorough Spark Test)
(J. Reeves)
This is assuming that there is absolutely no spark on any cylinder.
To test the ignition switch for shorts, remove all of the spark plugs, then disconnect the large RED electrical plug at the engine, then crank the engine, testing for spark by using a small jumper from the battery terminal of the starter solenoid to the small 3/8" nut connector on the solenoid which energizes it. If you now have spark, the problem is usually the ignition switch.
However, if you now have spark we want to make sure that the switch is indeed the problem and that there is no short in the instrument wiring harness between the engine's RED plug and the key switch. To test this, re-connect that large RED plug, then remove the Black/Yellow wire from the back of the switch and again test for spark. If you had spark on the previous test and now have no spark, a short exists in the wiring harness somewhere. BUT if you still have spark as per the previous test (disconnected RED plug), the ignition switch is indeed faulty.
If thru all of the above the spark does not exist at all, there is a possibility that a short exists in the engine's side of that RED plug. To test, re-connect everything that might still be disconnected during the above tests EXCEPT that RED plug, then remove the Black/Yellow wire from the powerpack connector. Now test for spark via the solenoid jump. If you had no spark before with the RED plug disconnected but do now simply by having that Black/Yellow wire disconnected from the powerpack, a short would exist in the engine's wiring harness. Should this type problem exist, cut the Black/Yellow wires before and after the RED plug connector, splice wires to make them longer, and bypass/jump over that RED plug.
The stator under the flywheel can be checked visually for a meltdown. Look closely at it. If there is any cracks and/or a sticky substance dripping down on the timer base and powerhead area, that would result in a AC voltage drop to the powerpack. Should this condition exist, replace the stator. Check the resistance of the stator with an ohm meter between the Brown wire and the Brown/Yellow wire. Check for whatever the proper readings should be in your service manual. If you have no manual, your local library may have one.
If throughout all of the above you still have no spark, the usual problem is a powerpack failure
Thousands of parts in my remaining stock. Not able to list them all. Let me know what you need and I'll look it up for you. Visit my eBay auction at:
http://shop.ebay.com/Joe_OMC32/m.html?_dmd=1&_ipg=50&_sop=12&_rdc=1
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(Stator "35amp" Melt Down)
(J. Reeves)
The usual characteristic or sympton pertaining to an engine that has a stator melting down is that it will have spark when cold, but will have weak or no spark when hot. Many engines will run fine at first, but after being shut down, then attempting to restart 30 minutes or so later will not start. However, after sitting and cooling down, the engine may once more start and run. Eventually the stator will fail altogether resulting in no ignition/spark even when fully cooled.
This pertains mainly to the 35amp charging stator BUT this problem has also affected other smaller ampere stators. Make a note that the stator on engines manufactured in and after 1973 are two fold components. There are a series of smaller coils which deliver AC voltage to the rectifier, the rectifier converts that voltage to DC voltage to charge the battery. There are larger coils that deliver AC voltage to the powerpack capacitor in order to energize the ignition.
The 35 ampere stator has two (2) large black coils located (usually) at the rear of the stator. This 35 amp stator runs extremely hot and even though the water cooled voltage regulator/rectifier may be in perfect working order, this type stator will in time have what is called a "Melt Down". This is when those two large black coils start to drip a sticky substance down upon the timer base and the powerhead. The result is that the outgoing AC voltage to the powerpack capacitor drops, and this in turn results in weak ignition and eventually no ignition.
If a rectifier on any horsepower engine has failed (keeping it simple), this results in having the voltage back up at the stator causing the stator to overheat, which in turn causes a stator melt down.
Thousands of parts in my remaining stock. Not able to list them all. Let me know what you need and I'll look it up for you. Visit my eBay auction at:
http://shop.ebay.com/Joe_OMC32/m.html?_dmd=1&_ipg=50&_sop=12&_rdc=1
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