One of the Yanmar
3GM30's on my boat had developed an electrical
starting problem wherein the engine
would not always (and eventually, would only rarely) start when the gear/throttle lever was in the neutral position. I had assumed that the contact switches on the controls were at fault, but even when they were bypassed the problem persisted. The factory starter button and ignition switch both worked and current
was getting to the solenoid.
I replaced the solenoid only to find that there was no improvement. Eventually a search on a commercial diesel
related site led to the solution: the wire on the standard Yanmar
harness was of insufficient gauge and, due to the length (and likely some deterioration of ) the factory non-tinned wire, there was a drop over the path to the solenoid that meant that insufficient current
was getting to the solenoid to engage the mechanical starter spline. Replacing the same with 8 gauge wire (the original was 12 guage) corrected the problem immediately.
Since the wiring
was attached to the cable on the lead to the diesel
, it seems that moving the lever would occasionally move or flex the wire into a postion that temporarilly corrected the problem. Now, even after re-connecting the neutral contact switches, it functions perfectly every time.
I am not sure whether anyone here has experienced a similar problem, although apparently it is not limited to the 3GM30