Old Mower Engine GREAT Teacher

[MikeK]

When I was nine I asked my father to get a gas mower because it started with a rope and you could just steer it around. He told me that I was the lawn mower engine and if it didn't start itself he would use his belt starter. Reel fun.

 

[C26Pinelake]

When I was in chemistry class the teacher was discussing heat and work and how heat is changed to mechanical energy, so I made a cutaway of a Briggs 4 stoke and a Power Products 2 stroke engines and mounted them on a display board. I brought it in so the class could see how they work.

Now, the bad news....... To my surprise, the next day the teacher had the news crew come to class and take my picture and he thanked me for GIVING this display to the chemistry class for keeps. What could I do!

Is it still at the school ? Wayne

 

[Rex_A_Lott]

I beg to differ here. Lawn mowers fire when the points open just like the model A. The only ignition system that fires when the points close is something that uses a vibrating coil like a model T. Then the coil is still firing when the coil points open, it just energizes the coil with the contacts closed.

The points have to close when the flywheel magnet is moving past the coil, or it wont fire. On a Briggs motor anyway, the points are always open, except when the magnet is moving past the coil, they close to generate the spark. If you get that relationship out of whack, such as with a sheared flywheel key, it wont work. The magnet can spin past the coil with the points open until you get tired of pulling the rope and that ******* wont fire to save you out of Hell.

 

[Tom Wesenberg]

I've seen those aluminum keys not sheared, but knocked a bit off from the blade hitting a tree stump or large rock, and this has been enough to upset the relationship of the magnet passing over the magneto armature and points opening and give NO spark. I'm sure glad my Kohler K series engines have the points out in the open.

 

[Rex_A_Lott]

When I was nine I asked my father to get a gas mower because it started with a rope and you could just steer it around. He told me that I was the lawn mower engine and if it didn't start itself he would use his belt starter. Reel fun.

Pop had an old reel mower that had once had a motor to make it self-propelled. I thought it was cool the way that it operated, so I drug it out of the scrap pile and tried to use it....but it was too heavy for me to push, and it didnt take me very long to figure out why it was in the scrap pile.

I've seen those aluminum keys not sheared, but knocked a bit off from the blade hitting a tree stump or large rock, and this has been enough to upset the relationship of the magnet passing over the magneto armature and points opening and give NO spark. I'm sure glad my Kohler K series engines have the points out in the open.

Pretty much the same way I learned about it too.

 

[DougT]

The points have to close when the flywheel magnet is moving past the coil, or it wont fire. On a Briggs motor anyway, the points are always open, except when the magnet is moving past the coil, they close to generate the spark. If you get that relationship out of whack, such as with a sheared flywheel key, it wont work. The magnet can spin past the coil with the points open until you get tired of pulling the rope and that ******* wont fire to save you out of Hell.

The points have to close to complete the circuit and allow the magnets and coil to generate a voltage and energize the primary circuit of the coil. When the points open it stops the flow of current through the primary and collapses the field causing the spark on the secondary side. The key has to time the creation of the voltage so its available when the points open. Set your model A points so they never close and you won't get spark either.

All points have to close sometime in the cycle but that isn't the point that the spark occurs. The spark always occurs when the points re-open. The only difference between the Briggs and the model A is that the Briggs is generating its own electric and the model A is using battery voltage.

 

[Terry NJ]

I had a Crosely that I used to run on sidewalks, I loved that little thing. Today, My friends just remind me of how ugly it was.
Terry

My neighbor had the same thing. I thought that was so cool to have a two cylinder go kart. I never had a go cart, but built a few motor bikes, and also used my 2 H.P. Briggs on my neighbors go kart. We'd run the local side streets until someone would call the cops on us.