I've been having the intermittant start problem on my M-15 (5411) engine. Had engine pulled this winter and while it was out had them replace the starter. I still have the intermittant start problem and will be heading down to install the wiring modifications outlined here and in the Project section.
Will jumper from the line side of the glow plug switch (or load side of the key switch - depends on arrangement and access once I cram myself into that port lazerette) to the line side of the starter switch with #10 gauge wire. As noted, this eliminates the need to hold down the glow plug switch when starting. This eliminates a little voltage drop across the glow plug connections and switch contacts as the juice heads to the starter button. It also eliminates the heavy draw of the glow plugs while you're trying to engage the solenoid and crank. You can still, and normally should, start it the same way. Hold the glow plug down and then simultaneously press the starter button. However, now, when restarting a warm engine, just press the starter. Or, if you are really low on battery power and still need the glow plug. Warm up on the glow plugs, then remove your finger from the glow plug button and hit the starter simultaneously. Your glow plug will still be hot, but you'll save a few precious available amps to kick in the solenoid and crank the starter.
Then will remove the Yellow-Red (#3 in diagram) wire from the load side of the starter button to the start solenoid and lift the other end from the starter solenoid. Then will replace it with a #10 gauge wire. This should give me one honking jolt to that pesky solenoid to give me reliable starts.
But here is my question. In the engine wiring diagram (and real life) there is a 20 amp fuse on the wire leading to the starter solenoid (#3 Yellow-Red). The fuse is located on the end of the wire near the solenoid. Shouldn't this fuse be locacted farther upstream near the instrument panel? Where the diagram shows the fuse, it provides no short circuit protection to most of this Yellow-Red wire, only to the start solenoid itself. While I'm installing my modification, I will be putting the in-line fuse holder closer to the starter button. Access to it should be relatively easy through the lazerette hatch. And it's one less component exposed to engine compartment vibration, heat, and oil.
This also made me look at the other 30 A fuse on the 12V battery supply (#5 red) wire. The fuse is located on the end of the wire in the control panel area. Shouldn't this fuse be located near the other end (line side) close to the battery/starter connection? This would better protect the panel wiring, particularly the red 12 V supply wire to the instrument panel. For fault protection there should also be a fuse near the alternator output on the (#6 orange) wire leading from the alternator output. This is another current source. However, lack of this fuse may be intentional. If this fuse blew inadvertantly you might lose control of the alternator voltage, damaging it and other system components.
Well, this afternoon I'm off to the adventures of contorting myself into the lazerette. If I'm not heard from, run down to Yankee Boat Yard and look for the feet sticking up out of Lady J's lazerette. Sounds like a scene from CSI
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