 1 So the tach on my Yanmar 2GM20 got intermittent, then died completely. The smallest tug on the sender cable freed it up, and a quick examination showed some pretty corroded crimp on connectors. That got me looking at the other connectors and the above is what I found. (Hint: the green ooze is not supposed to be there). Time to act. |
 2 Here's the original Yanmar cables; a short one at the engine end, another at the panel and a long extension in the middle. Upon removal, I was not impressed. The wire used for the sender lines was quite small gauge, untinned copper (and heavily corroded as a result) made up of not very many strands. This was HARDLY marine quality wire. I also found a whole lot of unused connectors, unused wire, multiple jumpers .. nothing that made me happy. Now, to be fair, it HAD worked for thrity years but it did not give me a warm and fuzzy feeling. |
 3 Here's my solution; a homemade harness with proper marine wire made by Anchor and a circular MIL connector with gold plated contacts. |
 4 Here's the original panel, not quite wired yet, but with the mating MIL connectors. The big one is for the harness to the engine, the smaller to a secondary panel of genuine gauges. |
 5 Here's a sub panel to be mounted in the engine bay. At the top is a big sealed automotive relay. It turns out that corrosion of either the key switch contacts or the starter button contacts is a common enough reason for hard starting. By using a sealed relay, no real current is required at the panel, which solves this potential issue. Another common problem seems to be that the fuse WELL HIDDEN in the harness get corroded and again, no starting. A serious Blue Sea systems fuse in the red block will fix that. |
 6 The (nearly) finished job. All that's missing is the cover. |
 7 The oil pressure senders. In the lower right, at the end of the black loom is the original sender for the stock idiot light. That's the one that makes the buzzer scream when starting the engine. The hydraulic hose beneath it is typical Alan madness. I like gauges. Idiot lights and buzzers are fine ways to let you know you're screwed, but I'm big on knowing that something bad is ABOUT to happen, not that it already has. So I need an oil pressure gauge, and I want to keep the idiot light/screamer as well (basic belt and suspenders philosophy). The conventional wisdom says "use a tee". Here's the problem; both senders are pretty big. The tee with senders on either end resulted in a badly cantilevered assembly just begging to shake itself to bits and fill a bilge with oil. Now, these Yanmars are just FULL of passageways for all manner of hot water accessories, sealed off with threaded plugs. Darned if there wasn't also one in an oil passageway, right below the existing sender. Sadly, it was in a space too crowded to directly mount the new sender; nothing is ever that easy. But an adaptor from Japanese weird thread to something standard, a hydraulic 90, some hose, a bit of oak and voila, a remote mounted sender with no fear of shaking. |
