Merc 260 Issue

Just got this motor and took it out on the water for the first time this weekend.

Ran great until I believe the power surged causing the fuse to my master power to blow as well as one of the switchboxes.

I am only getting spark on one bank after replacing the Master fuse, and after switching the switchboxes it is still the same side out, leading me to beleive its the switchbox not the stator.

My question is this, would a wiring issue have caused this problem to begin with? I was planning on replacing the switchboxes and the voltmeter in the engine but want to make sure I fix it 100% so the new stuff doesnt also get fried from a power peak as well.

Thanks for any help

Cameron

Corroded wires cause more resistance and more current draw....which will blow a fuse.

would the fuse blowing up front be related to the switchbox going moments later or is it a fluke? The wires seem to be fine.

Ill replace the fuse but Id hate to replace the switchboxes as well to have them go again from an problem I did not rectify

Quote:

---

Originally Posted by Go Time

Corroded wires cause more resistance and more current draw....which will blow a fuse.

---

More resistance causes a DROP in current draw, NOT a rise. V = I x R.

Corroded wiring can cause an open-circuit condition and loss of ignition, but it shouldn't blow a fuse. It takes a "short" condition or a defective component downstream to blow a fuse.

A voltmeter with a peak DVA adapter can be used to prove out the ignition components.

Which fuse do you mean by "fuse to master power"?
The switchboxes get their power from the stator as high voltage AC. There's no fuse to blow there.

I have all of my instrumentation set up to a master power switch on my dash. Nothing major. But I noticed it blew shortly before I lost the port bank so I am just unsure if it is related.. Could easily be a fluke, I am unsure as to why it blew in the first place

this switch also has nothing to do with the ignition or anything else, solely the gauges

Yuo are absolutely right pyro....its the heat genrated that increases...my mistake

Bad battery connections.


Dave

Dave could you please elaborate?

everything is getting power.

Could the rectifier going have caused the switchbox to break?

I'm an old electrician by trade. Fuses don't just blow for the heck of it, either a short or an overcurrent condition of some kind caused it. I would serriously look for that cause before chancing more high dollar electronics. Did you wire the dash and guages yourself? Sometimes a bad or loose ground wire can make crazy things happen, and eat electronic boards and such for lunch.

Any loose or dirty connection will cause high resistance. Corrosion inside batt cables under insulation. Just check every thing close, have replaced 2 stators, 3 alt on boats in the last month from people having loose battery or ground connections. Not saying that's your issue but sometimes the smallest things cause big problems.


Dave

What (I think) Dave is trying to say, is that if you happen to have a 9-amp or 15-amp charge system, and it happens to be one of the ones with NO regulator (which is really only regulated by the battery itself), and the battery cable connections happen to come loose, the 12V system voltage will spike high, which can cause the instrumentation to blow an accessory fuse.

Not sure how this could be related to the ignition loss, other than by coincidence. The charge windings of the stator are completely independent from the ignition side.

Quote:

---

Originally Posted by pyro

What (I think) Dave is trying to say, is that if you happen to have a 9-amp or 15-amp charge system, and it happens to be one of the ones with NO regulator (which is really only regulated by the battery itself), and the battery cable connections happen to come loose, the 12V system voltage will spike high, which can cause the instrumentation to blow an accessory fuse.

Not sure how this could be related to the ignition loss, other than by coincidence. The charge windings of the stator are completely independent from the ignition side.

---

Thank you very much for the insight