why not just fill in the right side channel with JB weld and remove the air check valve . Keep all parts and if later you want to “go original” you can just clean up the channel with a Dremel tool to restore it.
the air nipple will become your pump’s pulse line.
see link for the RD mod. the right hand channel picture from mumbles shows no drain hole at the bottom of the right channel so check your’s on the CD
https://www.aomci.org/forums/topic/gas-fuel-leak-help-on-a-1954-25hp-johnson-rd-15/
if you have no such drain hole on your rightand channel JB weld won’t hurt things anyway and the left channel will supply the pulses
up to you…
the purge valve mod is a whole diff. subject
Joining AOMCI has priviledges 🙂
