KE4AVB wrote:Disconnect the kill wire at coil and test. If still no fire then disconnect one spark plug at a time while the other plug wire is still in place and test. Reverse this and check again. If you fire with plug wire disconnected you a have shorted plug; otherwise, the ignition coil is bad.
No- That'd be Onan. Briggs is polar opposite - both plugs fire at the same time, they are on same circuit, but a shorted plug can cause no spark on the other side (path of least resistance and all that).... some onan twin ignitions the secondary (high tension) circuit is grounded through each other, needs the other side grounded to fire the testing side... they've been known to experience damage by trying to run them with a plug wire off one side, (since the path of least resistance is then wherever there happens to be any weakness in the coil's internal insulation) and can't do a power balance test on these by removing plug wires.38racing wrote:. Is it the opposed twin that I read you should not run with a plug wire off unless it's grounded ?
Arkie wrote:KE4AVB wrote:Disconnect the kill wire at coil and test. If still no fire then disconnect one spark plug at a time while the other plug wire is still in place and test. Reverse this and check again. If you fire with plug wire disconnected you a have shorted plug; otherwise, the ignition coil is bad.
You can find that ignition coil (magneto for less than $20.
No need to pull the flywheel, the coil is mounted on the outside of the flywheel. Just pay attention on the new mag and install with the very faint letters THIS SIDE UP. Set the air gap with a credit card. Be careful and do not twist off the mag mounting screws. Gently peck on the 5/16 head of the screw before trying to remove if all is rusted up. Steel screw going into aluminum. Use little bit of anti-seize when going back.
I've had good luck using the $15 mags on them old Briggs twins.
You can download a free service manual for that engine.
Like KE4AVB says or hints, sometimes new correct spark plugs will make them old Briggs twin come alive for awhile.
dart451 wrote:Arkie wrote:KE4AVB wrote:Disconnect the kill wire at coil and test. If still no fire then disconnect one spark plug at a time while the other plug wire is still in place and test. Reverse this and check again. If you fire with plug wire disconnected you a have shorted plug; otherwise, the ignition coil is bad.
You can find that ignition coil (magneto for less than $20.
No need to pull the flywheel, the coil is mounted on the outside of the flywheel. Just pay attention on the new mag and install with the very faint letters THIS SIDE UP. Set the air gap with a credit card. Be careful and do not twist off the mag mounting screws. Gently peck on the 5/16 head of the screw before trying to remove if all is rusted up. Steel screw going into aluminum. Use little bit of anti-seize when going back.
I've had good luck using the $15 mags on them old Briggs twins.
You can download a free service manual for that engine.
Like KE4AVB says or hints, sometimes new correct spark plugs will make them old Briggs twin come alive for awhile.
Arkie, isn't a credit card a tad too thick? What is meant by pecking the 5/16 bolt? Thanks.
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