powerpack motor stays running after turning master on.

[bouncer736]

Have a 1976 337G non turbo Skymaster. When I turn the master on the powerpack motor stays running only happens after setting over night. only way I can stop it is to open the gear doors and then hit the master then it closes right up and shuts off. anybody have the same problem? microswitch problem? powerpack problem? new power pack 4 years ago