Thread sizes on injection couplings

[savageseadog]

I'm looking to find out what size and type of threads are on diesel couplings. Most of the car ones I've come across have a male thread on the injector and a 17mm AF nut on the fuel pipe. The Yanmar ones (which is what I need to know are the other way around but I'm not sure if the thread is the same.
Anyone know please

 

[willie4646]

See if you can borrow a thread guage, it will tell you how many threads there are to a certain distance. The guage that matches your thread will have a number on it which will correspond to a chart number giving the thread size and pitch.
Willie