does anyone know what thread pattern cigarette boats used in the year 1987 gas fill cap .all the one from peko today dont work or do i have to change the complete unit

Perko used 2 diffrent thread types and then there is also Attwood. Take your boat to your dealer and see if he will let you try some till you find the right one. We stock the 3 most common ones just for this reason.

dealers here only have the peko with wrong threads