Is one wire the alternator wire for those engines that have a battery / electric starter ??

Are you sure its 4Hp not 3.5Hp ? The modern ie 80s onwards models had a electronic ignition and NO points. They were interchangeable ! one wire went to ground the other to the stop button/control. I dont think the points version has been available for decades. There were many models the numbers were stamped on the air duct over the head. If you need more info I will find my briggs manual ? Noel.

Edited By noel shelley on 18/07/2023 11:09:49

The loose wire is likely to a kill switch that shorts the coil primary to shut off the engine.

Bazyl

All genuine Briggs & Stratton ignition/carburation parts come with fitting instructions. The points system has been obsolete for years. The replacement converts the old points system to electronic ignition with minimal fuss. The spare lead is for the sop start or emergency stop start. I note the cost has risen significantly since replacing the ignition for a friend a few years ago. However, much like Myford who else would be supporting 40 – 50 year old machnes or engines.

If you require fitting instructions send me a PM with your email address and I can forward a copy to you.

Robert Butler

Edited By Robert Butler on 18/07/2023 17:54:37

If the coil is of the points type there will be a gap both sides between the coil and the laminations ! If it's electronic there will only be a gap on one side. it is switched by the action of the flywheel magnet. To set it up put 2 or 3 sheets of paper between the magnet and the laminations, this will pull the mag onto the flywheel and then do up the 2 small fixing bolts and remove the paper. That will set the air gap. IF electronic you DO NOT need the points – remove them. Do NOT loose the flywheel key ! It is aluminium do not use a steel one ! If the key has even the smallest step in it replace it. Noel.