Johnson 18hp High Speed Orifice Plug Correct Size?

[oldfarmall]

Hello-

Have a 1964 Johnson 18hp model FD-18E outboard. Need to know correct high speed orifice size. Old part number is 309415, which supercedes to 328544 orifice size 63D. I pulled my original high speed orifice out and it was stamped "64". What does this mean. Also, are there other sizes available for this motor. Mine is running too rich at high throttle. I have ordered the 63D orifice. Any way to check if someone opened up this orifice plug to a larger size? Thanks for the help in advance.


Jesse

 

[boobie]

Re: Johnson 18hp High Speed Orifice Plug Correct Size?

Unless you have a whole box full of special drill bits there's no way to check. Put the new jet in and see what happens.