duckbill valve size?

[4_Ever_Newbie]

Anyone know what diameter is the duckbill valve in a 2004 260 Searay Sundancer Vacuflush toilet system ?

Westmarine sells 2" and 1-1/2". Also found somewhere else they have them in 1-3/4" as well

Toilet won't flush and plan to attempt disassembling the valves seeking for an obstruction...(don't have access to the boat to measure the diameter right now).

Thanks in advance for any tips

 

[goose1]

The 1 1/2 fits they changed to 2 inch in 2006

 

[4_Ever_Newbie]

Thanks!