no spark

Phillip Poitevin

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no spark in 190 cc briggs and stratton engine. I have a new coil installed with proper gap. Flywheel magnets are clean. I have disconnected kill switch. Still no spark. Holding bare plug wire gives no shock.
 

Phillip Poitevin

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I tried it upside down with no luck. The coil has an ohms reading of 5.8 to 6.1 ohms (spelling). Is it possible that flywheel magnets are too week?
If flywheel has moved from original setting because key has broken, would that stop it from firing at all?
Thanks for your quick response.
 

Scrubcadet10

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If the flywheel key is broken It Will throw off ignition timing but It Will still spark. The magnets should try to pull in a object at least about 1" away.
 

Fish

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Take into a dark garage and test for spark by holding the side of the plug to the block, while someone else pulls the rope. If you are spinning with a drill, it usually isn't fast enough.
 

StarTech

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I tried it upside down with no luck. The coil has an ohms reading of 5.8 to 6.1 ohms (spelling). Is it possible that flywheel magnets are too week?
If flywheel has moved from original setting because key has broken, would that stop it from firing at all?
Thanks for your quick response.
Coils with the electronics on board can't be tested using an ohms meter due to internal configuration of the electronics. The only test most of us can do is the go/no go test; otherwords either it works or don't work. Also note your reading appears to be taken on the high voltage (secondary) side and would be actually 5.8 Kohms to 6.1 Kohms. THis would be a normal reading. The primary side which is tested between the kill tab and coil's frame will be in the one ohm range. Actually the new Magnetron coils reads 1.5 - 1.7 ohms when the electronic are not shorted out. If the D13003 transistor should short out then the resistance drops to 0.5 -0.7 ohms when the coil;s primary winding is not shorted. Now if the coils primary should happen to open then the resistance will be well above 1.7 ohms. Even if all the ohms reading are right the coil can still be inoperative.
If the flywheel key is broken It Will throw off ignition timing but It Will still spark. The magnets should try to pull in a object at least about 1" away.
The way the service manual has magnet strength tested is to have the flywheel on its side with the magnets facing up. Then placing the flat end of a 10 inch screw driver across the magnets. IF the magnets hold up the screw driver then they are strong enough.
Take into a dark garage and test for spark by holding the side of the plug to the block, while someone else pulls the rope. If you are spinning with a drill, it usually isn't fast enough.
Most Briggs Magnetron coils require a minimum rpm of 350 rpms to generate a spark.
 
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Phillip Poitevin

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Thanks to everyone. I will proceed by sending the new coil back and try another one. I have never had these problems before. usually a new coil results in spark.
 

VRR.DYNDNS>BIZ

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no spark in 190 cc briggs and stratton engine. I have a new coil installed with proper gap. Flywheel magnets are clean. I have disconnected kill switch. Still no spark. Holding bare plug wire gives no shock.
A little known issue with a very popular plug wire - if totally metal shielded plug connector, a internal brittle white insulator can become cracked inside the metal shield when we wiggle the connector to disconnect the plug wire from the plug. In doing so, this brittle insulator cracks. Once cracked, the base of the metal shield connects to the base of the plug and thus spark is routed to the plug base when connected, yet will show spark outside in testing in open air where the ground is not connected to the shield. So an intermittent or permanent short to ground prevents proper internal spark. This is so common, we have a fix we have employed nearly 100 times in our shop. We peel the shield off the plug wire, eliminating the ground short instead of replacing with the faulty design.
 

namvet

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If the flywheel key is broken It Will throw off ignition timing but It Will still spark. The magnets should try to pull in a object at least about 1" away.
If the flywheel key is broken It Will throw off ignition timing but It Will still spark. The magnets should try to pull in a object at least about 1" away.
If the flywheel key is broken, the flywheel probably won't even turn and the shaft will just spin inside the flywheel. Clean the magnet surface and coil surface and stick a piece of paper between the two, about ..002" gap and usually that works for me. Make sure to blow off any steel wool or dirt. They need cleaned often if left in a cold barn over winter. I always try the easiest fix, which is a new plug.
 
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