Mercury SmartCraft Gauge (HELP)

[Yard-Ornament]

I have recently (two summers ago) purchased a 1998 KenCraft Challenger 250. It has twin 2003 Mercury Optimax 200s. The SmartCraft gauges work (LCD screens need repair)…. But my major problem is as follows:

I just recently had to replace both Alternators on each motor. I took the boat to a local mechanic in New Bern, NC (Tommy Dunn / Tommy’s Outboards). In getting the boat back and running it today I encountered a problem. My Speedometer Gauge will only show Fuel Tank 1 (Starboard) and Oil Tank 1 (Starboard). Somehow or another Fuel Tank 2 (Port) and Oil Tank 2 (Port) will not show up. This information only shows up on my Speedometer Gauge. I contacted Tommy (mechanic) and he told me that he never went into the wiring of things, as he was quickly able to determine that the Alternators were my problem. Only two wires had to be disconnected from them…. So I downloaded the manual and was reading how to go into the settings (Cal 1 and Cal 2). Well I noticed that the Port Tach will not allow me access into Cal 2. I am only able to access Cal 1. If I understand correctly the Tachs are where I find the Fuel Cal and Oil Cal. But the Fuel level and Oil level show on my Speedometer….

How do I gain my Fuel Tank 2 and Oil Tank 2 on my Speedometer?

[Fishing Addict]

Post your serial numbers, Don will get you fixed up pretty quickly.

[Yard-Ornament]

Well I am the FNG to this stuff…. What serial numbers do you want posted?

[greg88]

The serial numbers of each engine.

[Yard-Ornament]

2003 200XL OPT (S/N OT737388)
2003 200CXL OPT (S/N OT760970)

[Yard-Ornament]

I have traced wires from both oil tanks and both fuel tanks, all appear to be connected. I have downloaded and printed out a parts diagram for this motor and it only shows 1 fuse location and I have checked the fuses. I am missing something but I just don’t know what…… It’s just really weird that I took it in for a battery issue, it would show both fuel tank fill levels, both oil tank fill levels…. The alternators on both motors were my issue and replaced. And now my Port Tach will not go into Calibration Mode 2 (Cal 2)….. Which is where as I understand it, will show my Fuel Tank 2/Oil Tank 2.

I am probably making this more complicated than it is… Looking for something major when it’s probably minor.

[EuropeanAM]

Each engine can input values for TWO TANKS. Tank 1 and Tank 2.

Tank 1 is a pink w/black stripe wire, Tank-2 is a blue w/black stripe wire. Each runs to the "boat" harness (6-pin) plug which is either on the right side inside the cowling, or somewhere between the cowling flange and the back of the boat.

Start checking that wiring at the engines. It's unusual that you would have FOUR tank inputs setup in a twin application, since the Speedo drives from the STB engine (most commonly).

[Yard-Ornament]

I have finally made it back to look over what you sent.

I have two fuel tanks and two oil tanks.

Fuel Tank 1 (Starboard) has a Pink/Black and Orange/Black. Oil Tank 1 (Starboard) has a Blue/Black and Orange/Black. These wires run from the tanks to the Starboard Motor.

Fuel Tank 2 (Port) has a Pink/Black and Orange/Black. Oil Tank 2 (Port) has a Blue/Black and Orange/Black. These wires connect into a harness that runs directly to the Port Motor. **This is the side that my boat is not detecting. **This is the Tach that will not allow me to go into Cal 2 mode (which is where it allows you to calibrate these tanks). This was all working before I had the alternators replaced. I have chased the wires, they are not broken anywhere, plug directly into a harness (I guess it’s an extension harness), that plugs directly into corresponding connectors, which run the wires to the ECM.

[EuropeanAM]

Make certain that there are no other GROUND wires connected to any of these 4 (four) sensors. CANNOT intermix 12V and 5V (black w/orange stripe) grounds.

INSPECT TO MAKE SURE THERE IS A COMMON GROUND CABLE BETWEEN EACH ENGINE'S CRANKING BATTERY (ie: Port cranking battery to Starboard cranking battery).

See if you can get pictures of the under-dash wiring. Specifically interested in the configuration of Junction Box(es) and cables going to each engine (or each instrument).

I suspect the Port tach "thinks" it's a SLAVE instrument (rather than the master instrument for the PORT engine).

[Yard-Ornament]

I checked this afternoon on your response:

Negative Battery Terminals are all linked: Port Cranking Battery (Negative Terminal) to Starboard Cranking Battery (Negative Terminal) and Auxiliary Battery (Negative Terminal) to Starboard Cranking Battery (Negative Terminal). The Auxiliary Battery runs the VHF Radio, GPS, Stereo, 12V Plug, Lights, etc.

I checked on ground wires. What I did find was a ground wire that went from Fuel Tank 1 to Fuel Tank 2, then it tied in to each Fuel Fill Port on the side gunnel, then went to a Negative Bus Bar. I have not seen this done before, but not sure if it was done by previous owner being the fuel tanks are aluminum and he wanted to make sure they were grounded for spark purposes.

I am was able to take several pictures and trying to figure out how to load them so that you can see them. Fuel Tank 1 and Oil Tank 1 did not plug into a harness inside the boat but ran directly to the Starboard Motor and plugged directly into a connection under cowling. It is Fuel Tank 2 and Oil Tank 2 make a connection inside the gunnel of the boat and then run to the Port Motor. I did not take a picture of the connections under the cowling for the Starboard nor Port Motor. I will get that tomorrow and post those pictures as well.

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[EuropeanAM]

My recommendation here would be to REMOVE the Black w/Orange wires from ALL tank locations. Dummy them off so there is NO way for them to reconnect.

Replace them with a BLACK (battery 12V-) ground.

This is important because you have tanks with the USCG required Bonded Ground (12V-) AND a 5V ground (on the same aluminum tank). Big no-no.

As best I can tell (from the very limited view of your J-box wiring), you have two engines plugged into the one side of a 6-gang junction box, and two tachs + 1 speedo plugged into the other side.

From the PORT side tach, try performing a MASTER RESET. Make sure that BOTH engine's keys are in the ON position when doing this (it needs to recognize and configure as a PORT (Outside) tach, at Station-1. If it does anything else, it won't work right.

[Yard-Ornament]

Don

Thank you so much. I had to do a Master Reset on the Port Gauge. As soon as it finished it went to working and showed my Fuel Tank 2 (in Percentage rather than Gallons, but I can live with that) and Oil Tank 2 (it shows in Gallons). So got the lower and upper cowling back on, now to send off the gauges to Gauge Saver and see if they can fix the LCD screens in the gauges. I will be working on getting the wiring done as you stated for the negatives (Thanks a million for that advice).

And….. While they are gone, do some research to see why these gauges are reading to me to have a Horn Fault and Trim Fault…..

Sincerley,

Rob

[EuropeanAM]

Horn fault: Warning horn not detected OR circuit resistance is outside of the pre-programmed parameters.

Trim Fault: Need to know exactly what that reads.