Stick the rubber cone to the spinner and pull the trigger.
Stick the cone to the spinner
firmly. With wimpy starters and high compression engines, back the prop gently against compression, so the starter can get up some speed before the engine hits compression.
If you just have a prop nut, turn the rubber cone around -- most are designed so that the resulting small hole will center the starter on the prop nut, and the pressure of the rubber against the prop is enough to start the engine, if you do the back-to-compression thing above.
Many will tell you don't use an electric starter that it will damage the motor.
Somewhere in my stash of Cox engines I have an example of a case and prop drive that are chewed up by an electric starter. There needs to be a thrust bearing that can take the load without getting chewed up. Most engines recent-er than the 70's or so have a thin steel washer between case and prop drive, or some such. If that's not there then the crank pin will ride against the backplate, or the prop drive will ride against the case.
I've also heard from more than one diesel aficionado that it's very easy to bend a rod against a diesel's extra compression if you use an electric finger. Again, I suspect that an engine designed for such starting will last better.
I have used one for years and years and haven't hurt a motor yet. On the other hand many in my club get a motor to start with one flip. So to use or not use is up to your own personal view. Another one of those arguments that does not have a definitive answer.
I have some engines that are balky with a hand flip, that start right up with an electric. For CL I mostly use my hand, but I have starters around for the balky ones.