Starter Solenoid wiring question

[LeslieTroyer]

on my 83 Catalina 36 there is a fuse directly attached to the starter solenoid. It is shown on the wire diagram for the M25. Can any one explain the purpose. It isn’t to protect the long run of wire up to the ign switch to starter lug to battery switch to 300A battery fuse.

And anyone see a problem putting a 30A fuse after starter lug and removing this one??

Thanks
Les

 

[Stu Jackson]

Les,

In these two items from this page: http://www.c34.org/wiki/index.php?title=Manuals under Engine Manuals:::::

• M-25 Service Manual - Searchable PDF - (initial M-25 manual) -

• M-25 Workshop Manual - Searchable PDF (early M-25 manual) -

there are wiring diagrams. Are these the kind you are referring to?
IIRC one shows a 20A fuse. I don't understand what it's supposed to do. Note also these old manuals have the ammeter, which you removed from your boat as I did mine.

 

[LeslieTroyer]

Those two manuals don’t reference it - this CD diagram for harness replacement does https://www.catalinadirect.com/index.cfm/feature/73/z2644--z2855-instrument-panel-wiring-diagram.cfm

Your manuals look like they predate my engine and the CD post dates it. The engine had a fuse to the starter solenoid that looked original the same as shown in the CD drawing.

I have no fuses or CB’s at the panel which is like the drawings you show.

Going from #2 cable to a #10 and then to #16 with no fuses along the way sounds like a way to invite problems.

Since @mainesail had one of these I hoped he would weigh in on fusing.

Les

 

[LeslieTroyer]

 

[JimInPB]

Those two manuals don’t reference it - this CD diagram for harness replacement does https://www.catalinadirect.com/index.cfm/feature/73/z2644--z2855-instrument-panel-wiring-diagram.cfm

In that diagram, it looks to me like that 10 amp breaker is there so that if you get a short in a less critical device like a tach or accessory, it will not cause you to loose the function of the more mission critical devices like the low oil light or the high temp light.

If the switch & wiring is up to handling a 30 amp load, then you can probably get away with using a 30 amp fuse rather than the 10 amp breaker that is listed. I do not know the capacity of that switch.

 

[jssailem]

Do not see an issue with your 30 amp fuse and #10 wire. But the diagram shows a 10amp fuse. I suspect it is for the #14 wire and the circuits of the engine gages.

 

[Stu Jackson]

Les, I was too busy looking at various wiring diagrams to recognize the question.

Could it be THIS?:::::::::::::::::::

http://c34.org/bbs/index.php/topic,5078.msg32211.html#msg32211

Please read the references to the other posts in that link, let's chat tomorrow.

 

[jssailem]

@Stu Jackson By Jove I think he’s got it. Why yes he’s got it.

 

[LeslieTroyer]

@Stu Jackson I can get to the page you reference but can’t open the two links in the article. I agree if the holder goes bad you would get a fail to start. If the holder was at the start button instead of at the engine it would also understand the purpose.

@JimInPB I understand the purpose of the CB. Like Stu’s provided diagrams I don’t have that CB on my panel. The fuse in question is on the starter solenoid where it can only protect the 6” of wire between the fuse and push terminal at the starter.

 

[LeslieTroyer]

Here is a photo that I ripped off from @mainsail under the universalwire harness upgrade article. I believe this was his M25.

You can see the ATG holder (smallest red wire #14??) in the center of the photo with the protected end going behind the large red cables to the solenoid terminal. This is the extent of wire the fuse protects.

The #10 wire (fatter small red with yellow ring terminal) at the top of the starter lug is the one I’m proposing putting a 30A fuse on, because it could deliver up to 300A if there was a short further down the wire.

 

[Stu Jackson]

@Stu Jackson I can get to the page you reference but can’t open the two links in the article. I agree if the holder goes bad you would get a fail to start. If the holder was at the start button instead of at the engine it would also understand the purpose.

Les,
Odd, not opening...try the two from here
1. http://c34.org/bbs/index.php/topic,4556.0.html

2. http://c34.org/bbs/index.php/topic,1637.0.html

Kloeber says it's (the fuse) useless in the wire to the ignition.

 

[Stu Jackson]

The #10 wire (fatter small red with yellow ring terminal) at the top of the starter lug is the one I’m proposing putting a 30A fuse on, because it could deliver up to 300A if there was a short further down the wire.

OK, so what is the purpose of this wire? Does it go to the ignition button?

 

[LeslieTroyer]

Yes the #10 runs un fused to the ignition where it is used un-fused for glow plug[relay coil] and starter solenoid, fuel pump and, alarm circuit - then on newer panels to a CB then gauge lights and blowers. It steps down to #14 and #16 for some of those circuits.

The links above opened - they talk about failure of fuse holder and how it needs 15-20A to not blow but no rational on why it is needed. Looking at starter specs - the relay pulls ~38A for a fraction of a second as it is pushing out the “bendix” then ~12A to hold it and energize the starter.

 

[TomY]

Yes the #10 runs un fused to the ignition where it is used un-fused for glow plug[relay coil] and starter solenoid, fuel pump and, alarm circuit - then on newer panels to a CB then gauge lights and blowers. It steps down to #14 and #16 for some of those circuits.

The links above opened - they talk about failure of fuse holder and how it needs 15-20A to not blow but no rational on why it is needed. Looking at starter specs - the relay pulls ~38A for a fraction of a second as it is pushing out the “bendix” then ~12A to hold it and energize the starter.

I just changed a similar arrangement on my boat. Original: A #10 gauge wire, unfused, ran from the alternator to the starter/battery lug, then to the ignition switch where it powers the glow plugs. From that post on the ignition switch, I've added a fuse to protect the smaller panel wires, that take power from there.

New: I just took the #10 wire off the starter and wired it to the On side, of the On/Off battery switch for the starting battery.

In moving it, I placed a Maxi fuse holder just off the starting battery switch, to fuse all the # 10 gauge wire to panel and glow plugs. I've slipped in a 50 amp maxi fuse to cover the #10 gauge wire. Testing, the glow plugs aren't blowing the fuse.

 

[TomY]

I just changed a similar arrangement on my boat. Original: A #10 gauge wire, unfused, ran from the alternator to the starter/battery lug, then to the ignition switch where it powers the glow plugs, and ignition panel wiring. From that common ON post on the ignition switch, I've added a fuse to protect the smaller panel wires, that take power from there.

New: I just took the #10 wire off the starter and wired it to the On side, of the On/Off battery switch for the starting battery.

In moving it, I placed a Maxi fuse holder just a few inches off the starting battery switch (where there is a convenient bulkhead to mount the Maxi fuse holder), to fuse all the # 10 gauge wire to alternator, panel and glow plugs. I've slipped in a 50 amp maxi fuse to cover the #10 gauge wire. Testing, the glow plugs aren't blowing the fuse.

 

[LeslieTroyer]

@TomY what you’ve done make perfect sense to me. What I don’t understand is how there can be 10,000’s of Universals out there and no one is making a fuss like for the trailer plugs and amp gauge, or were previous potential failures blamed on the trailer plugs.

I’m looking at it now for two reasons. That area is a rats nest of wires running off and grounds from who knows what on any available bolt. I also had starting problems traced (finally) to a bad battery cable and I want to be sure it will crank over and start when I’m solo sailing.

I have even replaced that exact holder when the original failed not giving any thought to its purpose.

 

[Stu Jackson]

The links above opened - they talk about failure of fuse holder and how it needs 15-20A to not blow but no rational on why it is needed.

Les, the first link I posted yesterday is to the Critical Upgrades topic and suggests reading a later post. In that later post Ken Kloeber talks about how the fuse is useless, why and what to do.

This:

http://c34.org/bbs/index.php/topic,5078.msg56975.html#msg56975

 

[LeslieTroyer]

Thanks Stu guess I didn’t read down far enough.
I’ll check later engine manuals for configurations but my rewire is moving forward.

 

[Maine Sail]

Here is a photo that I ripped off from @mainsail under the universalwire harness upgrade article. I believe this was his M25.

You can see the ATG holder (smallest red wire #14??) in the center of the photo with the protected end going behind the large red cables to the solenoid terminal. This is the extent of wire the fuse protects.

As you read in the article that fuse is not replaced to protect that wire, in that location, I install it in that location for two reasons.

#1 If the start button sticks, and they can and do, far too often, pulling that fuse kills power to the solenoid. Pulling the fuse at the engine panel end is often far too difficult in an emergency situation.

#2 An ATC fuse holder, in that location, makes a great tap in point for a remote start button for engine service work such as oil changes, fuel filter changes or "bumping" then engine over for valve adjustments.

The #10 wire (fatter small red with yellow ring terminal) at the top of the starter lug is the one I’m proposing putting a 30A fuse on, because it could deliver up to 300A if there was a short further down the wire.

Absolutely! That wire needs OCP, and on newer engines it has it.. On that engine, (not my engine BTW) there is a MIDI fuse mounted a few inches away. Because the distance was more than 7", to get to the MIDI, the wire is encased in heat resistant loom.

 

[LeslieTroyer]

As you read in the article that fuse is not replaced to protect that wire, in that location, I install it in that location for two reasons.

#1 If the start button sticks, and they can and do, far too often, pulling that fuse kills power to the solenoid. Pulling the fuse at the engine panel end is often far too difficult in an emergency situation.

#2 An ATC fuse holder, in that location, makes a great tap in point for a remote start button for engine service work such as oil changes, fuel filter changes or "bumping" then engine over for valve adjustments.



Absolutely! That wire needs OCP, and on newer engines it has it.. On that engine, (not my engine BTW) there is a MIDI fuse mounted a few inches away. Because the distance was more than 7", to get to the MIDI, the wire is encased in heat resistant loom.

Thanks Rod.

I’ll put in approperate fuseing and encourage others to do the same!! Is the MIDI better than the ATC in this usage?? I’ll also fuse the 10-14/16 connections at the panel.

My current plans are to remove the glow plug switch and replace it with a time delay off connected to the IGN Sw. Then use the old Glow plug wire to drive a LED lamp at the panel showing glow plugs on (glow plug relay 78). Then a relay driven by the Glow plug 78 relay to 85 and 30-78a goes between switched power and alarm power.

The result of this is the glow plugs will come on with power. I won’t have to count seconds to start as the buzzers will start once the glow plugs time out. (Or listen to buzzers when glow plugs are on). Much like old Volvo’s worked. My glow plug life might be reduced by 10% but they are cheap and I can always start the engine before they time out if it is hot.

Les