Original quote edited... keeping it short.
1 - If I'm to understand you, the SID will suffice for the SIG when I order parts.
2 - The tach had been acting normally the last time in the water three months ago. The fuse blows at very random times. This problem has only developed since getting back into the water.
3 - I removed the cover... I detected a slight odor of burned electrical circuitry. I cannot pinpoint this odor's location. I did replace the fuse and turned the key on but the tach still sits at 4k. I'm of the impression the tach is driven by the voltage regulator. I haven't a clue how to go about troubleshooting the tach.
4 - Is there a procedure for troubleshooting this type of tach and voltage regulator?
5 - When I first launched the other day, we got off of the trailer and back to bank to load partner. The fuse under the engine cowl was blown. Replaced and restarted and got maybe 100 feet from bank in no wake zone when fuse blew again. Replaced fuse the second time and restarted. Third time fuse blew we were running at about 4000 rpm and a good two hundred yards from where we started.
1 - I'm not one for abbreviations my friend. The SID & SIG will need an explanation.
2 - Sounds to me that you have an electrical component failing in the worse way.
3 - The tachometer is driven by the 6 pulse charging rate of the stator that is located under the flywheel. Observe it closely to see if a sticky looking substance might be dripping down upon the powerhead area.
However, although the stator drives the tachometer, a failing water cooled voltage regulator/rectifier will cause the tachometer to malfunction... I suspect that this is what is taking place, the odor of electrical circuitry, the malfunctioning tachometer, etc.
4 - Yes, I devised the following which checks the tachometer and the water cooled voltage regulator/rectifier all at the same time (below).
5 - Hard to say... BUT... in all probability the voltage regulator/rectifier is no doubt the cause of all your problems, including the fuse.
Let us know how the following test works out for you pertaining to the tachometer & regulator/rectifier.... and also be sure to check that stator for a meltdown problem (dripping sticky stuff).
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(Testing Tachometer With Water Cooled Regulator/Rectifier)
(J. Reeves)
A quick check is to simply plug in a another new tachometer as a piece of test equipment. If the new tach works properly and the old tach didn't, obviously the old tach is faulty.... but usually boaters don't carry around a spare tach (see below).
A faulty rectifier wouldn't damage the tachometer, the tachometer simply wouldn't work. This is due to the fact that the tachometer operates off of the charging system and the rectifier converts AC voltage to DC voltage, enabling the charging system. A faulty rectifier disables the charging system, and the tachometer simply doesn't register.
However.... those water cooled regulator/rectifiers that are used on the 35 ampere charging systems (and some others) bring into play a different type problem, and as you've probably found out, they are really a pain to troubleshoot via the proper procedure. There's an easier way.
The tachometer sending/receiving setup operates off of the gray wire at the tachometer. That same gray wire exists at the engine wiring harness which is connected to the engine electrical terminal strip. You'll see that there is a gray wire leading from the regulator/rectifier to that terminal strip, and that there is another gray wire attached to it. That other gray wire is the wire leading to the tachometer which is the one you're looking for.
NOTE: For the later models that DO NOT incorporate a wiring terminal strip, splicing into the "Yellow Wire" mentioned will be necessary.
Normally the Gray wire leading from the tachometer is attached at the terminal strip to another Gray wire which leads from the water cooled voltage regulator/rectifier...... remove the gray wire that leads to the tachometer. Now, find the two (2) yellow wires leading from the stator to that terminal strip. Hopefully one of them is either yellow/gray or is connected to a yellow/gray wire at the terminal strip. If so, connect the gray wire you removed previously to that yellow/gray terminal. Start the engine and check the tachometers operation, and if the tachometer operates as it should, then the regulator/rectifier is faulty and will require replacing. If the tachometer is still faulty, replace the tachometer.
If neither of the yellow wires from the stator is yellow/gray, and neither is attached to a yellow/gray wire, then attach that gray tachometer wire to either yellow stator wire, then the other yellow wire, checking the tachometer operation on both connections.
I've found this method to be a quick and efficient way of finding out which component is faulty.... the tachometer or the regulator/rectifier. It sounds drawn out but really only takes a very short time to run through. If the water cooled regulator/rectifier proves to be faulty, don't put off replacing it as they have been known to catch on fire with disastrous consequences.
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