The electric clutch will not stay engaged on my 1620 cadet the mower deck will run only if you hold up the switch I have swaped it out with another switch and no difference what or where do I look for the problem it acts like it may be a safety type issue

Did you put in a new switch or a used one.
Check you wiring coming to the switch cubs have one hot wire that kicks it on and the other one holds it.