1993 year Onan MDL4 marine generator has developed a short such that if I press the rocker switch (S11 or no. 7 in parts book) either to "start" or "heat" positions, it immediately trips the main DC on/off breaker. (CB 11 in schematic, part 16)
From what I gather on marine forums a common cause of this is either a short in one of the glow plugs or one of the gauges...but apparently not the case here...disconnected wire to glow plugs, no difference, disconnected gauges, no difference.
Also substituted K11/part 23 relay from good generator to bad (I have two), no difference.
All overload switches and other switches check out with proper continuity.
Have examined the electrical control box and the engine itself carefully for chafed wires...all seems good. The short extends to the wires that connect to the fuel injector to open it's internal solenoid. I disconnected a wire in the electrical box once (months ago, can't remember which one now) that allowed the (Cummins) engine to turn over normally without tripping CB11, but engine wouldn't start as no voltage was going to the fuel injector solenoid....thus no fuel allowed past it.
Any ideas what else to check ?
(as yes the print quality and size of the schematic suck but it's all I have)
From what I gather on marine forums a common cause of this is either a short in one of the glow plugs or one of the gauges...but apparently not the case here...disconnected wire to glow plugs, no difference, disconnected gauges, no difference.
Also substituted K11/part 23 relay from good generator to bad (I have two), no difference.
All overload switches and other switches check out with proper continuity.
Have examined the electrical control box and the engine itself carefully for chafed wires...all seems good. The short extends to the wires that connect to the fuel injector to open it's internal solenoid. I disconnected a wire in the electrical box once (months ago, can't remember which one now) that allowed the (Cummins) engine to turn over normally without tripping CB11, but engine wouldn't start as no voltage was going to the fuel injector solenoid....thus no fuel allowed past it.
Any ideas what else to check ?
(as yes the print quality and size of the schematic suck but it's all I have)