Props spin when enabled

With the very latest (today) firmware on board my 3DR quad flys and loiters fine. But the props all spin slowly as soon as the APM is enabled. I tried adjusting the throttle min parameter but that makes no difference. I have calibrated the ESCs successfully.
What parm needs adjusted to keep the props from starting to turn on enable?

[quote=“jjwhite”]With the very latest (today) firmware on board my 3DR quad flys and loiters fine. But the props all spin slowly as soon as the APM is enabled. I tried adjusting the throttle min parameter but that makes no difference. I have calibrated the ESCs successfully.
What parm needs adjusted to keep the props from starting to turn on enable?[/quote]

MOT_SPIN_ARMED. I very strongly recommend keeping it - it is designed to prevent dangerous situations.

Thanks for the response. I found the parm in the Standard list late last night. And I understand your point regarding safety.

Next issue is the sonar is not working. The right unit is selected as enabled and I verified that in the full parm list. But the sonar voltage and sonar distance are both zero all the time. Is there another place it has to be enabled, or a selection for what pins on the APM is is plugged in to? This one worked fine for a year on previous version of the firmware.