Reply To: Johnson FD-12 Won’t Run

[Don]

Bob Wight wrote:

With the original air pulse pump fed from the air nipple on the manifold, I had removed the reed plate check valves and plugged one of the two ports to get pressure and vacuum off one cylinder (I’ve used this approach on several other motors when I used an air pulse pump).  See pic of reed plate plug.

 

In the 2nd test run with the new pump fed from the bypass cover, I left the reed plate plug in place and capped off the air nipple on the manifold.   Not sure if it will make a difference, but today I pulled the manifold and reed plate and re-installed the check valves on the reed plate.   In pulling the manifold and reed plate off, I also opened up the carburetor again just to make sure nothing was amiss there – it all seems OK.

OK, so you only plugged up one of those ports?  I “think” that should work fine provided the pressure nipple is capped off.  The only other thing to question/check is that the two different intake manifold gaskets are installed properly.