Starter wiring with in line fuse?

[Dubble D]

All,
Little help here. To begin this is a universal diesel in a 1984 30` Newport. Don`t think it matters as a starter should be a starter. Had a no start issue and found it to be a broken wire from ignition switch to starter motor. There was a in line fuse in this wire and it had come apart at the corroded connection at the fuse holder. Quick fix at the islands was to ditch the fuse and splice wire together.
I have never seen a fuse in this wire, Am I missing something? Should I put one back in?

[Paul54]

I have a 84 Universal or Kubota diesel with out any fuse for the starter solenoid. Not all boats fuse the starter circuit. I did however try to go help another boat this weekend with a Yanmar that had a blown fuse for the starter solenoid. He got it replaced and was running again.

Proper sized fuses are always a good idea. They can prevent fires, and alert you to other problems.

[alctel]

I would definitely fuse the starter circuit.

Battery Bank Fusing Photo Gallery by Compass Marine How To at pbase.com

[ullar]

For what it's worth. I'm having a 400A ANL fuse close to my starting battery. That has been sufficient for Volvo Penta MD21A 4-cilinder. To keep maintenance down both fuse holder and fuse are gold plated.

[barnakiel]

A fuse goes in the solenoid circuit, not the starter circuit. We have a VP MD7 and there is one. (I think about 35A)

If there ever is one in the starter circuit, it will be a huge one. Just look at starter specs, they are often 1000w and bigger. I can't remember typical wire ampacity but I am sure the fuse will be a monster.

b.

[skipmac]

Originally Posted by barnakiel

A fuse goes in the solenoid circuit, not the starter circuit. We have a VP MD7 and there is one. (I think about 35A)

If there ever is one in the starter circuit, it will be a huge one. Just look at starter specs, they are often 1000w and bigger. I can't remember typical wire ampacity but I am sure the fuse will be a monster.

b.

In the starter circuit even for larger diesels 200-300 amp fuses work. I think I have a 250 or 300 amp fuse on my 58 HP Westerbeke and hasn't blown yet, even with the solenoid stuck and the starter wouldn't disengage.

[ullar]

Originally Posted by barnakiel

A fuse goes in the solenoid circuit, not the starter circuit. We have a VP MD7 and there is one. (I think about 35A)

If there ever is one in the starter circuit, it will be a huge one. Just look at starter specs, they are often 1000w and bigger. I can't remember typical wire ampacity but I am sure the fuse will be a monster.

b.

A fuse in the solenoid circuit is such a no brainer, a definite must and should be sized according to solenoid wire size.

You sure thought of 1000A not watts? Still, everybody I've talked with are happy with reasonable size starter battery fuses.

[Dubble D]

Thanks all,
I`m off to pick up a quality fuse and put it back in that line. Sometimes we need to stop and ask the `Cost to Gain `question!
Thanks for the link Alctel, good stuff, I`ll be going a little further now and look at fusing all the battery banks at the terminals.

[Stu Jackson]

Originally Posted by Dubble D

Thanks all,
I`m off to pick up a quality fuse and put it back in that line. Sometimes we need to stop and ask the `Cost to Gain `question!
Thanks for the link Alctel, good stuff, I`ll be going a little further now and look at fusing all the battery banks at the terminals.

While you're thinking about that try these posts, you may have to visit different pages of the thread and I also suggest you read the embedded links, too, same issue.

CRITICAL UPGRADES - DO THESE OR ELSE!!!

[MarkSF]

I recently re-wired the panel to the engine, deleting the trailer plugs. The inline fuse holder in the wire to the starter solenoid was replaced with a much better quality waterproof one, moved close to the panel for ease of access (also a less damp location).

After all, if the purpose of the fuse is to protect the solenoid wire, doesn't it make sense to put the fuse as close as possible to the source of the voltage, not at the other end?

LED lighting, soundproof, Sailor's Solutions Inc.

[deblen]

Originally Posted by MarkSF

I recently re-wired the panel to the engine, deleting the trailer plugs. The inline fuse holder in the wire to the starter solenoid was replaced with a much better quality waterproof one, moved close to the panel for ease of access (also a less damp location).

After all, if the purpose of the fuse is to protect the solenoid wire, doesn't it make sense to put the fuse as close as possible to the source of the voltage, not at the other
LED lighting, soundproof, Sailor's Solutions Inc.

I believe you are correct Mark. Putting fuse at solenoid end does not protect the wire (from start switch to solenoid) at all. It should be at the start switch end,or,better still,the source for the whole start switch could be fused close to the bat. supply(usually the big pos term on solenoid that has the heavy cable to bat.)
Fuses should be close to the source. IMHO

[deblen]

Originally Posted by Stu Jackson

While you're thinking about that try these posts, you may have to visit different pages of the thread and I also suggest you read the embedded links, too, same issue.

CRITICAL UPGRADES - DO THESE OR ELSE!!!

Thanks for link.
I agree with KWKloeber! Fuse at wrong end. Fuse in wrong wire.

[Stu Jackson]

Originally Posted by deblen

Thanks for link.
I agree with KWKloeber! Fuse at wrong end. Fuse in wrong wire.

You're very welcome. It is always pleasant to meet someone who understands. All the best.

[barnakiel]

Originally Posted by skipmac

In the starter circuit even for larger diesels 200-300 amp fuses work. I think I have a 250 or 300 amp fuse on my 58 HP Westerbeke and hasn't blown yet, even with the solenoid stuck and the starter wouldn't disengage.

Whatever works.

With a 1.5 hp starter motor the amps induced at the first flash of a second the starter kicks in may easily blow up a 200 A fuse (on a 12 V starter, anyways). Plenty depends on how cold it is and what engine one has. A Westerbeke (if similar to those used in gensets) is way different from an old Volvo with an old school flywheel ...

I think maybe 200 / 300 A fuse is fine with lighter wires, but on my boat the wires are ... just imagine. Etc. So to say the size of the fuse, when present, will vary quite a bit between boats.

Big fuses are difficult to buy offshore. They are also difficult to fix (short) in a boat that may be rolling and pitching in the dark (that's exactly when such things happen - mostly at 04:00 hours).

Is it a good practice to have a circuit breaker on this circuit BTW?

I like the idea of protection on the starter circuit much as my boat came without one.

b.

[MarkSF]

One advantage of using the MBRF fuses at the batteries is that if one blows, I can juat switch to the other battery bank until I fix it.