Question on B&S twin #422700 motor

Was having trouble starting, would turn over but no spark or very int spark.

The battery started going down from cranking so I charged it up.

Once the battery was charged the spark returned and now runs.

After cutting the yard I shut it off and went to start it again and it wuld turn over fast but no spark again.

I put the charger on again and turned it over and it started right away.

I was under the impression these engine were magneto powered for the ign coil, so a battery voltage should not be needed except for the starter to operate.

Is this engine have a different type of ign coil that need a good 12vdc to produce spark during starting?

Your motor has 1 coil w/2 plug leads. If the gap between coil
frame (armature) and flywheel has grown, your starter may have to spin the FW
at a higher RPM in order to induce a spark.
Also, your coil could be getting weak.
I had a similar B&S engine that would crank up and run just fine, but
if yoiu shut it down it would not restart until it cooled off.
I believe the coil was on its last legs on that one...........

Also make sure the coil frame is well grounded......

Ok, understand.

Question is the black wire (not the spark plug wires) that comes out the motor is connected to the start switch.

Is this wire the shut off coil wire and grounded when turned off?

When i had the plugs out of the engine and was turning it over (really fast) I would get a int spark, but when the battery charger was hooked up they sparked right away.

So it seems like I needed full voltage for the coil, but it is a magneto type coil, right?

spudgun said:

Ok, understand.

Question is the black wire (not the spark plug wires) that comes out the motor is connected to the start switch.

Is this wire the shut off coil wire and grounded when turned off?

When i had the plugs out of the engine and was turning it over (really fast) I would get a int spark, but when the battery charger was hooked up they sparked right away.

So it seems like I needed full voltage for the coil, but it is a magneto type coil, right?

Click to expand...

Correct on the black wire. That is the kill wire.
Correct on magneto ignition.
Only thing I can imagine is that the starter spins the FW faster when spinning under charging voltage, which is typically 14.7v or so.
A fully charged battery is only about 12.7volts.
That increase may induce a spark more readily than spinning under battery voltage.