Below is the list of tables from the database along with their columns and datatype. Need to generate an accurate SQL query for the question.
Only use the columns present in the respective table. Only use the columns which are required to generate the SQL query. Only use table joins if required and not otherwise.

### Tables ###
TABLE: CREATE TABLE table_42850 ( "Year" real, "Chassis" text, "Engine" text, "Start" real, "Finish" real, "Entrant" text )

### Question ###
What start has a ford cosworth dfx as the engine, a year later than 1981, and kraco enterprises as the entrant?

### Accurate SQL ###

SELECT "Start" FROM table_42850 WHERE "Engine" = 'ford cosworth dfx' AND "Year" > '1981' AND "Entrant" = 'kraco enterprises'