Can you describe how you started it? Position of the throttle, choke, etc. Did the prop spin when it started? Often when you first start some motors, they will rev and on the hose, it can be a little un-nerving. Do you have a tack? When I would start my Johnson, it wouls run at about 1500rpm for a minute and then back down to idle. If it started in gear, you need that fixed ASAP.
My procedure was to pump the buld, turn the key to on and press in a few times to prime, then turn to start. The motor would fire right up, but race for a minute. I don't know much about your set up but maybe can shed some light.