My ford aerostar shakes after I start it?

Reset the fuel shutoff switch. Should be located in the rear somewhere.It IS located behind the passenger side kick panel.

he built a car.

It is hard to say for sure not knowing much about what you have but here is a list of things to check or try found in my Haynes manual. Make sure you have fuel- with a carburetor the choke could be...

stuck chock

THE STARTER IS WET. WONT FIRE UP WHEN WET. INSTALL A STARTER SHIELD. GOOD LUCK THE STARTER IS WET. WONT FIRE UP WHEN WET. INSTALL A STARTER SHIELD. GOOD LUCK