90 amp starter fuse

grassm

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Yes, I know it's an old thread, but I ended up here and so might someone else.
I have a single engine Rinker 260EC. No room to speak of for getting to the 90amp starter/solenoid mounted fuse.
As was stated, 90 amp fuse feeds a 50amp and 15 amp(violet/w red tracer). There is another flat fuse mounted to the fiberglass rail to the side of the starter. Not sure what it protects at the moment. I just got my boat back after 8 months, took it out once and all was fine. Second time, dead. Wouldn't crank and an no instruments. What I found was the nut on the primary red wire from battery at the solenoid was loose. The 90amp fuse was blown and the 15amp inline fuse (just behind the 50amp CB and the slave solenoid).
My questions:
1. Is there a reason to mount the 90amp to the solenoid? I'm thinking that the copper plate would conduct heat to the internal fuse element, causing it to fail from heat from the starter/solenoid. Just a guess.
2. If it's not there as a thermal protection for the starter/solenoid, can I move it somewhere else, so it's easy to get to when it blows (and I'm out in the Gulf and there's as bad storm coming......)?
3. No one ever answered the question. What part of the electrical system is at risk if you don't use the 90amp fuse? If it's not mounted to the starter/solenoid, it can't protect the starter from overheating. Once it blows, the engine will shut down and you won't be able to crank or start. From what I see it feeds the 50amp, a 15amp(vio/red) gauges, ignition, and starter circuit. I didn't find anything that was not protected by a lower value fuse or CB. Which points me back to protecting the starter/solenoid from overheating.

I really think that it's there to protect the starter/solenoid from overheating. What a really dumb-ass setup. Dead in the water until you crawl down in the engine compartment to replace/remove the fuse.

Writing this post helped me decided what needs to be done. I'll use the fuse so it's there to protect the starter/solenoid, but I'm going to run wires that will allow me give me a second circuit fuse (that I will have to manually take care of), THAT I CAN GET TO IN A HURRY!!!!!
 

Bondo

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Ayuh,..... Welcome Aboard,...... I gave you a thread of yer own, insteada that 10 year old, 2 page long thread that you hi-jacked,....

Dependin' on which motor, 'n the way it's dressed has alot to do with that big fuse on the end of the battery feed cable,.....
Which btw, brings up the question,......
Just what motor are ya workin' on,..??..??
 

grassm

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Mar 27, 2022
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Ayuh,..... Welcome Aboard,...... I gave you a thread of yer own, insteada that 10 year old, 2 page long thread that you hi-jacked,....

Dependin' on which motor, 'n the way it's dressed has alot to do with that big fuse on the end of the battery feed cable,.....
Which btw, brings up the question,......
Just what motor are ya workin' on,..??..??
Mercruiser 350HP. 383 ci ? Re-manufactured by Mercruiser. Thanks for my separate post.
 

Bondo

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Mercruiser 350HP. 383 ci ? Re-manufactured by Mercruiser. Thanks for my separate post.
Ayuh,..... If it's a Efi, or Mpi, the fuse is important to the motor's electronics,....
 

grassm

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Ayuh,..... If it's a Efi, or Mpi, the fuse is important to the motor's electronics,....
It's EFI. 383 Mag Stroker. So it pretty much protects the ignition system. It doesn't need to be located under the engine, so I'll put a 90amp oem part in place and put heavy wire from each side up to a 90amp resetable, waterproof marine breaker. Thank you for your help Bondo! I'm sure I'll have other question as my Rinker education continues.
 

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  • RInker engine plate 383 Mag Stroker.jpg
    RInker engine plate 383 Mag Stroker.jpg
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Bondo

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It's EFI. 383 Mag Stroker. So it pretty much protects the ignition system. It doesn't need to be located under the engine, so I'll put a 90amp oem part in place and put heavy wire from each side up to a 90amp resetable, waterproof marine breaker. Thank you for your help Bondo! I'm sure I'll have other question as my Rinker education continues.
Ayuh,.... More like the induction system,....... ;)
 

grassm

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Ayuh,.... More like the induction system,....... ;)
Ummmm. How can I tell what I have then. I can take more pics if that will help. I ran it but only for a less than 2 seconds, twice. It starts right up. I really want to learn everything about the boat before it strands me somewhere.
 

Bondo

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It's EFI. 383 Mag Stroker. So it pretty much protects the ignition system. It doesn't need to be located under the engine, so I'll put a 90amp oem part in place and put heavy wire from each side up to a 90amp resetable, waterproof marine breaker. Thank you for your help Bondo! I'm sure I'll have other question as my Rinker education continues.
Ummmm. How can I tell what I have then.

The Efi is 'puter driven,....
 

Bt Doctur

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Aug 29, 2004
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19,291
that fuse link protects the alt wiring in case of a failure, The main RED power wire is connected to it also for a reason only a mercruiser engineer can answer. Your main power is protected by the 50 amp CB.
When I have the replace the 90A block i install a 90a maxi-fuse instead. Its a lot esier to get to and replace.1648827928309.png
 

grassm

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Checked with two local mechanics......they both said....it's just where they put the fuse. So, I'm putting a new one in, but i'm wiring a 90amp marine breaker in parallel to it. and
that fuse link protects the alt wiring in case of a failure, The main RED power wire is connected to it also for a reason only a mercruiser engineer can answer. Your main power is protected by the 50 amp CB.
When I have the replace the 90A block i install a 90a maxi-fuse instead. Its a lot esier to get to and replace.View attachment 358141
I installed the 90 amp fuse in the original place, because I could not get a firm answer as to why it is where it is. I'm putting an 80amp waterproof CB (the kind that has a push button to trip it and a rectangular flag/arm that drops down when tripped) in parallel to the 90a fuse. I'll leave the breaker off. When it blows next time I just raise the engine hatch and flip the breaker. I'm fairly sure the first one popped because the nut that holds the fuse to the starter solenoid was loose, causing extra heat to build up from the poor connection. It's been a rough learning curve, but it won't be long before I know where to look for problems and work arounds.
Thanks everyone for the help.
 
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