Small generator engine will not start

Old 02-16-17, 07:40 PM
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Small generator engine will not start

Equipment= craftsman 4.2 kW generator model number 580.32674
7.8 hp Engine=Generac model=220
model year = 1997
engine number=98912
generac family number=SGN 216 uig 1ra:em
It has a nikki carburetor.
numbers on the carburetor are n86; c1535; c120012.

I bought this non-runner 2 weeks ago. Previous owner said it had spark but that the carburetor needed attention.

I found that the sediment bowl gasket was leaking. I disassembled the carburetor and cleaned the carburetor by soaking the metal parts in soapy water in a heated crock-pot. Then I soaked the metal parts 4 hours in a carburetor cleaning tank. I blew out the orifices with an air compressor. The fuel shutoff needle looked good. The fuel float had no leaks. I assembled the carburetor using a new sediment bowl gasket and a new gasket between the carburetor and the intake manifold. I replaced the gasket between the carburetor and the air cleaner too.

I measured the compression at 78 psi. The engine may have compression release. Do you think it has compression release? Then I placed a small amount of 30W oil in the cylinder [enough to cover the cylinder walls]. The compression was 82psi.

I removed the spark-plug to run the compression test. Then I connected the removed spark-plug terminal to the spark plug wire and attached a wire from the spark-plug ground electrode to the engine. I pulled the recoil starter several times and did not see a spark between the spark-plug electrode and the ground. I heard no cracking noise. I was surprised I had no detectable spark. I used a new spark-plug in the same way and did not detect spark.

I removed the engine shroud and unbolted the armature from the engine. The magnets on the flywheel are rusty. One of the armature legs is rust covered. The other armature leg is rusty too except on the trailing edge where the armature has been striking the flywheel. The strike point is bright metal and rust free.

This engine has a low oil level kill switch. I assume that when low oil levels exist the ignition spark is stopped. There is plenty of oil in the crankcase.

Where should I look to find the ignition problem?
Old 02-16-17, 07:49 PM
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Reassemble the ignition coil with a .010" gap between the legs and the flywheel magnets. Unplug the kill wire from the coil and check for spark. If it sparks, plug the kill wire back on. If it does not spark, the problem is in the low oil safety or kill switch or wiring. If it never sparks under any of these conditions, the coil is bad. Make sure the plug is properly grounded while testing. Wrap your wire around the threads of the plug.

BTW: Nice post, full of all the pertinent info in advance! Much appreciated!

Last edited by cheese; 02-17-17 at 12:22 AM.
Old 02-16-17, 08:41 PM
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BTW: Nice post, full of all the pertinent info in advance! Much appreciated!

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