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Ammeter Wiring

Your old Chris-Craft electrical system can be a challenge. If it runs on "juice" pose your questions and offer your advice here.

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mbigpops
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Ammeter Wiring

Post by mbigpops » Tue Jun 21, 2016 10:09 am

I have completed the wiring to my KL engine and everything is functioning properly - lights, horn, blower, engine starts and runs.

Only issue is when I turn things on there is no indication on the ammeter except for the horn which causes the needle to jump negative.

I am attaching two photos - one of the Chris Craft schematic close up of the ammeter and one of my engine wiring.

The Chris Craft schematic is somewhat confusing as it shows both the Ammeter (positive) and Oil pressure gauge (negative) together. My question on this is do the two connections on the left really represent the screw terminals ? In other words is the red wire from the starter on one terminal and the black wire from the generator on the other screw terminal ? This does not make sense as I would thing the source goes on one and the load on the other.

In my engine wiring photo does the black wire to the generator look like it is in the correct location ? I ran that wire to one side of the ammeter and then the other side go to power my fuse block (loads) assuming what I wanted to see on the ammeter was the load on the generator.


Any clarification based on experience would be appreciated.

Thanks

Mark
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Engine wiring 3.jpg
Engine wiring 1.jpg
1953 CC Rocket Runabout "Rocket Man"

Denis D
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Re: Ammeter Wiring

Post by Denis D » Wed Jun 22, 2016 12:59 pm

Hey Mark,

I'll give it a shot. I studied my schematic for my '48 Dlx which is the same as yours and putting on my old electronic technician hat, here is my take.

The red wire carrying positive voltage from the Battery (via the starter terminal) connects to the negative terminal on the dual gauge. Attached to the same terminal should be the blue wire going to the horn relay which essentially connects the horn circuit directly to the battery positive. This gives you the ability to blow the horn even when the boat is completely shut down. This also means that blowing the horn will not register anything on the amp meter so you should not be seeing needle movement when blowing it.

The black wire form the generator connects to the positive terminal on the gauge. Also connected to that terminal is the black load wire which feeds all the other circuits in the boat including lights, ignition, starter circuit, etc.

There should also be a yellow ground wire connected from the cross shaped distribution block to the case of the dual gauge.

In operation, if you turn on the ignition switch with the engine off, current flow will cause a negative deflection of the amp meter. The more circuits you turn on, the further the needle will deflect to the discharge side. Now with the engine running, if it is idling slow enough that the generator is creating less than battery voltage, the cut out on the generator will remain open disconnecting the gen output from the circuit and the gauge will continue to show discharge. When engine RPMs increase to the point that the generator is putting out higher voltage than the battery, the generator cut out will close connecting the generator output to the circuit and the current flow through the gauge will be reversed as current flows back into the battery and the gauge will show a positive charge rate.

I hope this makes sense!!

It sounds like you may have the black load wire and the blue horn wire reversed on the gauge terminals. As far as the gen cut out wiring, my understanding is that the new cut outs use diodes instead of relays and thus are likely sensitive to which way they are wired into the circuit. You will have to see if the terminals are marked.

Best of luck,

Denis D
Denis

1948 17' deluxe runabout

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Re: Ammeter Wiring

Post by mbigpops » Thu Jun 23, 2016 7:41 pm

Denis,

Thank you for the clear and understandable response. It makes sense to me now. Based on my electrical experience I was thinking all the load circuits would show on the ammeter instead of the battery charge and discharge.

Today I rewired the ammeter as you suggested and when I finished the horn blew on just battery and did not show on the ammeter. I also turned the key with the engine off and got a negative deflection (discharge) so I think I have it right now.

Just need to run the engine at low and higher RPMs and make sure the generator and cutoff relay are functioning properly.

Mark
1953 CC Rocket Runabout "Rocket Man"

Denis D
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Re: Ammeter Wiring

Post by Denis D » Sat Jun 25, 2016 12:13 pm

Mark,

That's good news, you should be very close to launch? Make sure to post photos when you splash her.

Denis D
Denis

1948 17' deluxe runabout

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Re: Ammeter Wiring

Post by mbigpops » Mon Jun 27, 2016 7:40 pm

Denis,

The list is getting really short .... shouldn't be too much longer ....

Mark
1953 CC Rocket Runabout "Rocket Man"

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Re: Ammeter Wiring

Post by mbigpops » Thu Jul 07, 2016 6:41 pm

Denis,

Maiden voyage was today and went off without a hitch !

I had no idea how awesome it was to be in one of these boats never mind drive it and own it. The ride was amazing and the reaction from onlookers was priceless.

Here are a couple really bad photos (low priority for today). I promise better ones in the near future.

Best of all is another Chris Craft lives and a rare Rocket at that !

Mark
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Wake Shot 3.jpg
Bow Shot 1.jpg
1953 CC Rocket Runabout "Rocket Man"

Denis D
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Re: Ammeter Wiring

Post by Denis D » Thu Jul 07, 2016 8:38 pm

Congratulations Mark, that's awesome!!!

It must have been a great feeling to have Rocket Man doing what it was built to do once again. A great accomplishment to be proud of.

I have a long way to go yet so stories like yours help keep the enthusiasm going.

Where did you splash it, we are up at Winnipesaukee this week.

Denis D
Denis

1948 17' deluxe runabout

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mbigpops
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Re: Ammeter Wiring

Post by mbigpops » Fri Jul 08, 2016 9:55 am

Thanks Denis.

It was on an small local lake here in Mass.

I think I need a little more time before I am ready for the big lakes.

Keep plugging. It will be over before you know it .

Mark
1953 CC Rocket Runabout "Rocket Man"

54 Skiff
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Re: Ammeter Wiring

Post by 54 Skiff » Sat Jul 09, 2016 12:51 pm

Great question and great response, both have helped me better understand the wiring as well. Also congrats on the launch, she looks beautiful.

May I ask where you purchased the wiring from? I'm going to replace my wiring and I like the looks of the wiring you installed.

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mbigpops
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Re: Ammeter Wiring

Post by mbigpops » Sat Jul 09, 2016 1:28 pm

Rhode Isand wire.

Of course I got to go there in person from m location.

Mark
1953 CC Rocket Runabout "Rocket Man"

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