Running a four stroke quickly will get you trained on tightening the prop They will back fire and spin even a properly tightened prop.

The plastic spinner back plates are a real problem when it comes to really tightening up the prop. I've mashed them quite flat to the point of not being able to get the cone on. I finally switched over the the Great Planes aluminum back plate with nylon cone.

http://www3.towerhobbies.com/cgi-bin...?&I=LXBMY0&P=7

I tighten my props with one hand. Position the back plate in relation to the blades and check that the spinner hole align with the screw holes in the back plate. With a new plastic prop, it is best if you use a leather glove here or you can cut your hand. I use a 6" cressent wrench but a correct size open end wrench would be better. Put the wrench on the nut so it has a spread to the prop about 10 to 15 degrees, what ever the nut position will allow. Grasp both the prop blade and the wrench and squeeze them together. Filp the wrench over on the nut, gaining another 15 degrees or so and squeeze again. Flip it again and squeeeze and repeat untill you have a dificult time gaining on the nut. Most four stroke have a lock nut, so do the same with it.

Don