"I replaced the coil on my 18hp Briggs engine model 422707 type 1510-01 date code 9312165b. Is there a part under the flywheel that may cause a problem? Also what is the most simple way to remove the flywheel?"

Why are you wanting to remove the flywheel? The only thing under the flywheel that might cause an ignition problem is the flywheel key. These do not usually shear unless the flywheel was not torqued properly when installing. Even if the flywheel key is sheared or partially sheared, it will produce a full spark, just not at the right time.

Did you install the new coil the right way? The spark plug wires exit the coil on the "back" side, away from the spark plugs then turn under the coil and exit the cooling shroud on the spark plug side. Some new coils are marked, aftermarket ones may not be.

The easiest way to remove the flywheel is with a B&S flywheel puller. They are not expensive and are essentially a flat bar with three holes in it. (Or 5 holes if it is a dual purpose for large and small engines) One is in the center and goes over the crankshaft end and rests on the loosened flywheel/crankshaft nut OR on the head of the loosened flywheel/crankshaft bolt on later models. Hardened bolts run thru the end holes into the 5/16" tapped bolt holes in the flywheel, one on each side of the flywheel. You can make the puller if so inclined. Tighten end bolts alternately and evenly. Will sound like you busted the flywheel when it lets go.

Walt Conner

Reason I was considering pulling the flywheel is that I saw wires running out from under the front of the flywheel. Thanks for the tip about where to run the wires from the new coil, I'll do what you said then try to start again. Thanks.

"Reason I was considering pulling the flywheel is that I saw wires running out from under the front of the flywheel"

Those are from the alternator, the charging system.

Walt Conner

Thanks again for the info. Could the new coil be defective? I gapped the new coil away from the flywheel and routed the wires as you said to do. I don't get any spark at all or at best once in a while. It was suggested by my local Briggs dealer to leave the ground/kill wire off that doing this would eliminate all but the engine. another question is does the Power Built series have a low oil shut down? Thanks.

I have never seen a 42 series that said "Power Built" on it and very, very few B&S have a low oil shut off switches on them. It is an option that could be added but that would operate thru the Kill Wire that goes to the coil, where you said you were told to disconnect.

Did you make sure the mounting surface where the coil attaches to the engine were bright, clean? Did you check to see if the coil was marked "This side out" or anything that way? The way I told you to route them should have been right. Are you able to take a picture of the engine, coil, flywheel and post it?

.008" to .012" clearance between the coil laminates and the flywheel magnets.

Does the starter spin the flywheel briskly?

Walt Conner

Thanks again for the additional info. If I have more questions I will post pictures of it. The coil is marked with this side out and it is gapped approximately those measurements, I used a business card as I saw in these forums. The starter turns the flywheel quickly. I'll try cleaning again. Thanks again.

"I used a business card as I saw in these forums. "

I wouldn't get too tied up on this if I were you.

Walt Conner

As of this time there is no spark and I have the kill wire to the coil disconnected. I run a separate ground to the battery from the coil.
How do you post the picture in this forum?

I am having same problem with 16 hp briggs and stratton. Think it is the seat switch or clutch switch causing the magneto armature to ground. Am trying to figure how to test this. Any help?

What makes these coils usually go bad is somehow voltage
is sent through the "kill" wire to them. If you have a coil with no spark, and the kill wire disconnected, then the
coil is bad. A good connection where the coil mounts is
needed as well. If you have installed a new coil, and
plugged up the "kill" wire and tried it, then disconnected
the kill wire, then tried it, and still no spark, then your kill wire circuit must have voltage, and you have destroyed
your new one.
That is why there is a no return policy on electrical parts.

Usually, the wires near the muffler, or the steering are in contact from damage, sending voltage that way.

For the last poster, you have to disconnect the kill wire from the coil to confirm that the coil is fine, then
follow the circuit through with an ohmmeter.

Fish

changed coil engine started right up ran good, shut off and woldn't start no spark replaced coil again this time left the kill wire off started right up ran good for a couble days shut down wouldn't start again no spark, don't have any idea please help if posible thanks Alf

After replacing two coil on my 18hp briggs / Huskee tractor, I realized that the ignition/headlight switchswitch was putting voltage to the kill wire through the light switch. I replaced the switch and put the lights on a separate switch and replaced the coil once more. Now all is OK.

I am fixing an 18hp and it fried the coil when I flipped the old rusty faded light switch! Thanks for pointing that out, Im thinking of making a new kill button , from coil to kill button to block? will this be ok ??