Ok, my opinion, based upon anecdotal evidence from people reporting in here. I can also attribute my opinion to my own experience and VMax ownership over 29 years.
When some random cylinder cutout happens there are two things I'd examine:
the fuel delivery system
the ignition
The fuel delivery system includes examination of the gas tank, fuel lines (filter too), the fuel pump, carburetors, and all the components and connections, including the air intake, from the airbox to the VBoost to the cyl heads.
The ignition includes the ignition pickup, the wires from it, the electronic ignition box, the high-tension coils, the spark plug leads, the spark plug caps, and the spark plugs.
Rust in the gas tank places fine particulate material into the carburetor passages, with the pilot jet in the jet block being the smallest place in the gas delivery system. In my consideration, that is the 'bottleneck' in fuel delivery where obstruction is likely to occur.
If the problem appears to stay in the same cylinders, and you've verified the gas tank is shiny-clean everywhere inside and that the fuel filter is new, and the carburetors have been disassembled with the jet blocks removed and their jets removed and a session of ultrasonic cleaning has been done, but the problem persists, then I would look at the ECU/ignition 'black box' and the possibility it is probably faulty. As the manuals say, "replace with one of known good operational quality" and see if your problem is solved.
Sean Morley's electrical components kit, where you pay for whatever components you need to fix your electrical issues, is a good resource to replace your ECU/ignition box.
When some random cylinder cutout happens there are two things I'd examine:
the fuel delivery system
the ignition
The fuel delivery system includes examination of the gas tank, fuel lines (filter too), the fuel pump, carburetors, and all the components and connections, including the air intake, from the airbox to the VBoost to the cyl heads.
The ignition includes the ignition pickup, the wires from it, the electronic ignition box, the high-tension coils, the spark plug leads, the spark plug caps, and the spark plugs.
Rust in the gas tank places fine particulate material into the carburetor passages, with the pilot jet in the jet block being the smallest place in the gas delivery system. In my consideration, that is the 'bottleneck' in fuel delivery where obstruction is likely to occur.
If the problem appears to stay in the same cylinders, and you've verified the gas tank is shiny-clean everywhere inside and that the fuel filter is new, and the carburetors have been disassembled with the jet blocks removed and their jets removed and a session of ultrasonic cleaning has been done, but the problem persists, then I would look at the ECU/ignition 'black box' and the possibility it is probably faulty. As the manuals say, "replace with one of known good operational quality" and see if your problem is solved.
Sean Morley's electrical components kit, where you pay for whatever components you need to fix your electrical issues, is a good resource to replace your ECU/ignition box.
