I don't know if you can see it in this pictures, but fitting from original primer pump is smaller that the new one. Maybe wrong primer part installed or variant?
Puzzler... I put the old fitting next to the new primer in the pictures. The old fitting is small enough that it can just slide in. The part uses a washer / rubber O ring. I guess I can just order the larger JIC 6 to 3/8", but what about the washer/ O ring? What is the official name of that?
I ran into this when replacing our primer pump last spring, and forgot to mention last night! oops!
The military version used a 3/8 orb fitting which is 9/16-18 thread with the o-ring. The only place I found the mil-spec version required bulk orders. The commercial version available today onesey-twosey uses a 3/8 NPTF which is 11/16-18 thread as
@Ronmar noted. You need new fittings between the boss and fuel lines to replace the male orb side with a male 3/8 NPTF. The NPTF fitting is tapered pipe, no washer or o-ring; just a little pipe dope.
Here is my final response to Rancor last spring which they confirmed:
So, dumb as a bump on a log.
The pump I am replacing has 3/8 orb fittings,( 9/16-18 ); though the 445R has 3/8 nptf fittings, ( 11/16-18 inch ).
Please confirm. No o-ring, Pipe sealant.
I can do that—
New fittings and pipe dope. She works and doesn't leak—
