Blowing Starter solenoid fuses

[hoplite666]

Years back I did the dog head mod. I had had a run on starter and melted the fusible link going down to the starter solenoid.
I replaced the damaged wiring and installed an inline 30amp fuse in place of the fusible link that had been there from the factory. Every six months or so that 30amp fuse will blow. Pop a new one in and wham bam thank you ma'am its good to go again for a period of time. Today I go to leave work, turn the key and nada. Check the 30 amp fuse and its blown. Get another one from the glove box, pop it in. Give the key a turn and nada. Blew that fuse too. I did this several times all with the same result. Decided I'd use a paper clip to jump it just to get home. Well the paper instantly melted when I turned the key. So I get a ride home and here I sit.
No signs or nothing out of the ordinary leading up to this. About a week ago I did the glow plug resistor bypass and installed the LMC headlight harness but this should be entirely unrelated.
Time and tools are limited at the moment and until I get my laptop squared away navigating this site and the TM's on my aging smart phone is a pain in the butt so any quick thoughts or places to look first would be greatly appreciated!

 

[NovacaineFix]

So, you don't have a fusible link at the starter but you have a inline fuse rated at 30 amps. I just want to make sure we are talking about the same thing.
Since that seems to be working for a short bit of time (6 months), did you ever think about installing a 40 amp fuse?

They make them in ATO/ATC regular size, I believe that's the biggest before going up in size to Maxi fuse.



Now the fuses are great, but they are not as robust as the fusible links are. The links can take larger current draws for a longer period of time before blowing/melting.
This is why they are used in high amperage draw items on cars/trucks rather than fuses, but if the fuse is working for you, can't argue with that.

Next step would e to up the size of the fuse to a Maxi and rn a 50 amp or higher to what you need without causing damage to the other circuits.

 

[dependable]

I would check for a short or damaged insulation from the 'doghead' relay to the solenoid.

 

[Tinstar]

Would a stuck starter solenoid cause this?

 

[hoplite666]

That's correct, no fusible link just this in line fuse holder. I'll try a larger fuse but the fact that it melted a paper clip has me worried. What's the amp rating on a paperclip? Haha haha
So I'll try a 40 amp fuse, that seems to be the largest with out going to one of those massive ones used on a stereo amp and I'll have a look at the doghead relay wiring
Thanks fellas!

 

[hoplite666]

Taking a quick look at it now in the parking lot at work. All seems in order. Pulled the inspection cover off to have a look at the bendix, well it was in the forward, extended position riding\stuck on the fly wheel. Used a pry bar to disengage it and gave it another whirl.
Fired right up.
Never had this happen before but I guess it was locked up and blowing the fuse. Perhaps my batteries are getting weak

 

[MarcusOReallyus]

Since that seems to be working for a short bit of time (6 months), did you ever think about installing a 40 amp fuse?

That's good advice for a situation like that.

But.... once he got to the "blows immediately" stage, that's very BAD advice.

The first situation, since this is not a stock setup, is probably just due to having a fuse that's too small, so going up a notch might be a good thing. A better thing to try first would be going to a slow acting fuse of the same rating.

Blowing immediately every time you try to use it means there is a short somewhere and a larger fuse is just going to allow more damage. Never use a larger fuse, or worse, a jumper of any kind when a fuse blows immediately as soon as it's used.

Now the fuses are great, but they are not as robust as the fusible links are. The links can take larger current draws for a longer period of time before blowing/melting.
This is why they are used in high amperage draw items on cars/trucks rather than fuses,

Yeah, except they aren't much anymore. Slow-acting fuses can do anything a fusible link can do, and they are much easier to service.


Hoplite, glad you got it worked out. No harm in getting the batteries tested.


Good to meet you the other day.

I got about 105 gallons of clean #2 diesel out of that tank the other day, and another 28 of black stuff once I got it home. I'll see if I can filter that stuff to a usable state. The rest will feed my tractor. Freebies!

Oh, and the tank is currently being cut up to make an attachment for the tractor.

 

[NovacaineFix]

Marcus,

You are correct sir, I obviously did not read that part, (shame on me, )

 

[MarcusOReallyus]

You had me wondering, Nova. I had thought you knew better.

Wouldn't be the first time one of us missed an important part of a post and sounded off with the wrong advice!

 

[NovacaineFix]

Yeah, now that I look back at my response, I would have probably replied something like, "What, are you Crazy?"

The problem with late night posting and probably too many adult beverages on top os sleep deprivation, hey that's what I'm going to go with.
I can't remember why I would have suggested just putting a bigger fuse. My only thought was that maybe with his configuration, it was working but maybe he hadn't scoped it to determine the exact amperage it needed to work without blowing, since it seemed to be working for 6 months at a time. That's the only thing I could think of.


loco en la cabeza

I guess I just wanted to help out but, like you said, missed that key element and it snowballs from there.

Maybe next time, earlier and somewhat sober, yeah like that will happen...Not on my watch!