Fuse 4 on Scura

[Chuck]

What causes fuse 4 to blow over time? Looking back through my records, I see that it failed when I was out in SoCal several years ago. It just failed again while cranking. Out in SoCal, it failed when coasting to a stop.. <scratching head>

[gstallons]

what does your operator's manual say fuse 4 feeds ?

[docc]

Fuse 4 is the Ignition Switch. They deserve a good inspection, cleaning, and lubrication. 

[footgoose]

Here is a short (no pun intended) thread on my fuse 4 issue. Mine was an easy fix.

 

[Chuck]

This one won't be so easy, I'm thinkin.. from maintenance log:

Quote

4-1-15 30560 Suddenly quit out in the mountains. Replaced a 15 amp fuse.

This is the fuse that blew Thursday. Maybe I'll just buy a couple more? At 4 years per fuse, that might just do it..

[docc]

That seems rather un-pilot-like . . .

When was the last time the ignition switch was inspected for broken wires, cleaned and restored?

[Chuck]

•  

  1 hour ago, docc said:

  That seems rather un-pilot-like . . .

  When was the last time the ignition switch was inspected for broken wires, cleaned and restored?

  Yeah, you're right, Docc. I'll overhaul the ignition switch.   It's an easy job. It's no guarantee that it will fix it, though. I still think I'll buy a couple of spare fuses..

[docc]

All of the above?

[Chuck]

37 minutes ago, docc said:

All of the above?

Pretty much. Fuse 4 feeds the ignition switch, then about everything else on the motorcycle. Maybe I'll just put a penny in it..

Oh, and while I have it on the lift, is there any reason I can't piggy back a lead from Fuse 3 to the 30 pin on the start relay? That looks like an easy way to get some serious power to the starter..

[Kiwi_Roy]

On 8/4/2019 at 8:09 AM, Chuck said:

What causes fuse 4 to blow over time? Looking back through my records, I see that it failed when I was out in SoCal several years ago. It just failed again while cranking. Out in SoCal, it failed when coasting to a stop.. <scratching head>

With your new direct feed removing its largest load it shouldn't blow any more.

With the old wiring as the switch got dirty the current dropped down to a point where it was taking too long to pull the solenoid in although I have no idea why it blew while running.

If you look at the blown fuse it gives a clue, just a tiny gap indicates it was only mildly overloaded, a large gap indicates a short circuit.

Fuse 4 also feeds Fuse 6 and 7 through the ignition switch.

[Rox Lemans]

It's a sign of low voltage. Mine blows if the battery is low and keep trying to start it. It's somewhat rare but it happens.