Looking for wiring diagram/help please

[Old Ironmaker]

We are working on Little Buddy's 1985 Grew 237 Cuddy. Of course the wiring looks like a bowl of coloured spaghetti after all these years. Googled boat and model and have gotten reams of diagrams but can't read them and the diagrams are all jumbled up with other non related schematics, even a diagram for a human cornea is included!

Where can we find one and or where can we buy one? HIN tag at top Starboard side of transom is 2GR50008K485-237. There is a plate on the dash that says "ACF".

Thanks ahead of time all,
Johnny D

 

[Scott Danforth]

there are very few boat wiring schematics in existance

you will find the motor electrical schematic in the appropriate Mercruiser or Volvo factory manual, however very doubtful you will find a boat diagram

All manufacturers follow the same color code (SAE color code) [h=2]American Boat and Yacht Council Standards[/h]

Black	Ground	Negative / Neutral Main Return
Blue-Stripe	Tilt up and or trim out	Tilt and or trim circuits
Brown	Alternator Charge Light	Generator Terminal or Alternator Auxiliary Terminal to Regulator
Generator Armature	Generator Armature to Regulator
Pumps	Circuit Breaker or Switch to Pumps
Brown w/Yellow	Bilge Blowers	Circuit Breaker or Switch to Blower
Dark Blue	Cabin & Instrument	Circuit Breaker or Switch to Lights
Green or Green w/Yellow Stripe	Bonding System	Grounding Wires (if insulated)
Green Stripe	Tilt down and/or trim in	Tilt and or trim circuits
Grey	Navigation Lights	Circuit Breaker or Switch to Lights
Tachometer	Tachometer Sender to Gauge
Lt. Blue	Oil Pressure	Oil Pressure Sender to Gauge
Orange	Accessory Feed	Ammeter to Alternator or Generator
Common Feed	Distribution Panel to Accessory Switch
Feed	Accessory Circuit Breakers or Switches
Pink	Fuel Gauge	Fuel Gauge Sender to Gauge
Purple	Ignition	Ignition Switch to Coil & Electrical Instrument
Instrument Feed	Distribution Panel Electrical Instruments
Red	Instrument Feed	Distribution Panel to Electrical Instruments
Power Feeds	Positive Main Power (particularly un-fused)
Tan	Water temperature	Water temperature sender to gauge
Yellow	Generator Field	Generator to Regulator Field Terminal
Ground	Negative / Neutral Main Return
Yellow w/Red	Starting Circuit	Starting Switch to Solenoid

COLOR ITEM USE

Wire / Conductor Sizes
Length (feet): Determined by measuring the length of the wire from the positive (+) power source connection to the electrical device and back to the negative (-) power source connection. Note that the power source connection may be the battery, panel-board or switchboard.
Current (amps): Determined by adding the total amps on a circuit.
Wire sizes not covered in Table C or Table D may be calculated by using the following formula:
After calculating the Circular Mil Area (CM), use Table B to determine the proper conductor size. The National Fire Protection Agency and Coast Guard require that the next larger conductor be used when the calculated CM area falls between two conductor sizes.
CM=K x l x L / E
CM = Circular Mil area of Conductors
K = 10.75 (Constant representing the mil-foot resistance of copper)
I = Current - amps
L = Length - feet
E = Voltage drop at load (in volts)
For Example...
Q. A bilge pump draws 10 amps. The positive run is 11 feet from the power panel, including the float switch. The negative run is only 10 feet. What size wire?
A. Use the following formula to reach the correct answer:
CM = 10.75 x 10 (amps) x 21 (total length of run) / 0.36 (3% of 12v) = 6,271
The table below shows that 12 AWG wire has a CM area of 6,500 and is the correct choice. However, SAE wire has a CM area of only 5,833. Under NFPA and USCG regulations, 10 SAE wire must be used.
CM = 10.75 x 10 (amps) x 21 (total length of run) / 0.96 (3% of 32v) = 2,352
Ampacity is the ultimate safe current carrying capacity of the wire before damage occurs to the insulation, without regard to voltage drop. Because the insulation of most SAE wire types is not the same as ANCOR, this chart should not be used for other conductor types. Use Table C & D to find proper wire size to insure adequate performance.

18	0.8	1,600	1,537	20	17
16	1	2,600	2,336	25	21
14	2	4,100	3,702	35	30
12	3	6,500	5,833	45	38
10	5	10,500	9,343	60	51
8	8	16,800	14,810	80	68
6	13	26,600	24,538	120	102
4	19	42,000	37,360	160	130
2	32	66,500	62,450	210	178
1	40	83,690	77,790	245	208
1/0	50	105,600	98,980	285	242
2/0	62	133,100	125,100	330	280
3/0	81	167,800	158,600	385	327
4/0	103	211,600	205,500	445	378

AWG Sq. mm AWG CM area SAE CM Area Ampacity Engine Space
Outside Inside

 

[Old Ironmaker]

Thanks scott Danforth. That was fast. The guys at the building aren't computer savvy, actually can't turn one on. They think that the Internet has every piece of information ever recorded by mankind. I have tried to tell those old fogies there isn't an operating procedure for launching and landing the Space Shuttle but they think so.

Thanks again Scott.

 

[alldodge]

Is this a Merc, VP, OMC or other?

 

[Old Ironmaker]

It's a Mercruiser but not sure of the displacement, will know for certain in the morning as the boys are coming by for a coffee with some Zooma Zoom, after they clean my driveway covered in all this stupid white stuff with the tractor.

 

[alldodge]

Have some stuff for Merc. Being a 1985 could mean Pre of Post BIA wiring. Most the wiring is the same, the issue we run into is if its using current standards or the older stuff. Knowing what motor will also help. It probably will be current standards or at least real close to it

 

[HappyMotoring]

Hi Guys, I'd like to jump in on this thread to say THANKS for the great information. Scott's post above shows what a treasure trove of information is available on the forums. I've been lurking for awhile, trying to figure out which boat I'd like for a project. (Keeping in mind my kids and grand kids want to ski & tube) Last Saturday I found a pretty good 1994 Sea Ray 170. I was able to test drive it on Lake Granbury for an hour or so, and poke around on the hull and floor. Ran good and seemed solid. So of course, it followed me home...

So, "Thanks" to everyone here. Because of you, I was able to pretend I knew what the hell I was doing...

 

[Silvertip]

Hi Guys, I'd like to jump in on this thread to say THANKS for the great information. Scott's post above shows what a treasure trove of information is available on the forums. I've been lurking for awhile, trying to figure out which boat I'd like for a project. (Keeping in mind my kids and grand kids want to ski & tube) Last Saturday I found a pretty good 1994 Sea Ray 170. I was able to test drive it on Lake Granbury for an hour or so, and poke around on the hull and floor. Ran good and seemed solid. So of course, it followed me home...

So, "Thanks" to everyone here. Because of you, I was able to pretend I knew what the hell I was doing...

I can assure you that if you bought a boat -- you didn't know what you were doing and your wife/significant other would agree with you. Just joshin' of course.

 

[Old Ironmaker]

Like many things sometimes we know just enough to be dangerous. As far as electricity I bow to the experts, I have to call an electrician to change the batteries in my flashlights.

 

[HappyMotoring]

Ha! Ya'll are correct alright!! This is not my first boat, however, so I already know I'm setting myself up for some pain!! I retired a few months ago, and now find myself itching for a project...... so a 27 year old boat with a Mercruiser 3.0 ought to keep me off the streets, except to chase parts or something..

 

[Scott Danforth]

when I retire, I hope to have all the boat projects behind me so I can enjoy them..... the street-rod projects....... thats a completely different story.

 

[HappyMotoring]

I can sure relate to that, Scott. Spent the last 37 years working in the car and truck industry, hope to never work on trucks again!
Boats, now that is a different story, I still enjoy tinkering on things, although at a much slower pace. I'm determined to keep this boat project FUN.

Hmmm, wonder how long that Happy Horses$hit will last?

 

[Old Ironmaker]

Scott I brought the print out you gave here to the building today. It is very helpful, the boys would like to thank you and everyone elses help here,

AllDodge I forgot to ask what size Merc it is. I'll remember Monday.

HappyMotoring, best to you in your retirement and on your project. I've been out of a real job for over 10 years now. The lady I work full time for says if I do a good job she will let me sleep with her, I have a sign I hang around my neck now that says "Will work for food." Get one.

 

[Scott Danforth]

Thanks. however ABYC simply uses the SAE J378 which is a derivation of the Automotive codes. the colors are the same if you look under the dash of your car.

 

[HappyMotoring]

old Ironmaker, thanks for the encouragement. I've certainly slowed down a bunch, but still enjoy working on some project or three. I put in about 2 hours a day on my hobbies, keeps me halfway sane.