inline fuel lock will solve the problem only if you block also the vacuum port to the rear cylinder as well. i have thought about it but i had easy access to parts so was not a big deal.
If you have very difficult problems getting the part then temporary using a simple in line lock and attaching an blocked tube to the cylinder vacuum port will work, for the convenience its better to get a new valve set that will come with a new in tank fuel screen. but as i said buddy if that part is going to take 2 weeks+ to get to you then a quick fix will be what you said.
A way to check if it is the vacuum lock dumping fuel is to use a syringe and try to pull fuel out by connecting the syringe and drawing it multiple times to simulate vacuum suction!
Good luck and hopefully it will sort out your problem. ps if it is your problem then you will be able to draw fuel and your rear plug will be wet and fear cylinder will not be firing, and no pulse from the respected exhaust.
