curtthedirt

I have the Saito 150 and the prop sure seems to loosen up frequently when starting. I’ve got the double locking prop nuts on it but it still pops loose - frequently ?? Any suggestions??

2W0EPI

Try some 'blue' thread lock. Yeah, as convention has it, the correct way to spin the prop is ccw. which is why it comes loose as the normal shaft thread is cw, so the prop nuts are always spinning to open or unscrew the nuts.

Truckracer

My Feedback: (19)

The 150 was famous for aggressive firing when starting. I always found the easiest starting method on the 150 and even the better mannered 180 was a reverse flip against compression. You don’t back flip it through compression, just up against compression. If primed a bit wet, it will fire and run in the normal direction. Same method works for any large glo engines, 2 or 4 stroke. Very easy to do with a bit of practice. You can also easily back flip the prop just by gripping the spinner cone with thumb and two fingers.

Lean needle settings will also cause the engine to bang the prop loose.

Jesse Open

Back flip is a great method. Standard operating procedure here. The Saito double lock nuts are also a good move when properly installed.(Especially if you must use an electric starter)
Most people simply use too little torque also failing to use two wrenches.
Wood props should be re-tightened periodically.
Thread locking compounds on prop nuts can make nut re-tightening or removal more of a chore than it needs to be. Also a common reason we often see pliers mark scarred prop hubs.