A
Anonymous
Guest
The vacuum diaphragm started leaking, causing an overrich fuel mixture (fuel sucked into vacuum line) and fouled plugs. This was diagnosed when the vacuum line was replaced with a new transparent hose, fuel could be seen flowing in the line.
On teardown of petcock, noticed that in the "Prime" position, a small hole in the tapered plastic cylinder bypasses the diaphragm assembly.
Converted petcock to manual operation by plugging that small hole (epoxy), removing the diaphragm and capping the vacuum lines.
The former "Prime" position is now "OFF". "ON" and "RES" function as before, less vacuum.
On teardown of petcock, noticed that in the "Prime" position, a small hole in the tapered plastic cylinder bypasses the diaphragm assembly.
Converted petcock to manual operation by plugging that small hole (epoxy), removing the diaphragm and capping the vacuum lines.
The former "Prime" position is now "OFF". "ON" and "RES" function as before, less vacuum.