Newbie Question on Outboard Sensors And Wiring

[MonkeyBird747]

I’ve only ever run small tiller outboards and John boats, so pardon the rookie questions. Now I have a center console and installing a 2003 75hp elpto. I know that the tach sensor is already run in the 9-pin plug up to the throttle controls. What I’m not sure about is what other sensors, if any, are preinstalled? Are other sensors like water pressure, temp, Speedo, etc installed as needed? Aftermarket? I know I don’t have a water pressure sensor. I’m pulling some wire this weekend and I would like to go ahead and run wires for anything else I may need to install in the future. Other than an rpm gauge, what would you recommend? I have no gauges at all.

Also, I believe this oil injected motor has an oil level alarm. Not sure about a temp alarm. Is the alarm located in the engine cowling, or do I need to buy an alarm for the dash and run wires for that too?

MB

 

[Texasmark]

The alarm comes in on pin 3 of the "8 pin" engine to remote cable connector, tan/light blue stripe, on the engine proper. The alarrn horn could be in the remote control or in the wiring harness under the dash; and you could have an additional wire at the console/helm end of the cable. If the wire mentioned is sticking out of the harness at the console end you need to use a boat mounted alarm. Inside the engine is an OT alarm on the Tan wire coming from the sensor on the rear of the block's water jacket, lower left. It and the blue wires from the oil level tie into that connector mentioned, pin 3.

At the console end is/should be an external 4 pin connector with a Tan pigtail.......for dash warning light or remote horn. If using dash light or remote horn device, you need to feed switched 12v from the ignition switch on the remote control That would be on a red/purple stripe or purple, indicating switched 12v when the key is on.

That 4 pin connector is for tach and trim gauge if engine has a trim sending unit:

Tach wiring:
Black wire: Gnd...battery neg.
Purple: Switched power from ignition switch
Sender: Grey wire from engine.....8 pin connector pin 5

Trim winding: Same wires and terminals for power and gnd with the brown/white stripe bringing in the signal from the trim sender.

Speedometer is a rubber hose from the engine....pickup is a hole on the front of the Lower unit with a hose going up and out with the engine's electrical cables to the remote console/helm position. If your engine doesn't come with a hose, it needs to be added. Hose on the engine is easy to see where it attaches to the front of the Lower Unit.

Boat lights and such accessories (speedometer) are carried on boat wiring separate from the engine.

Water pressure would be sourced at the rear of the engine water jacket cover...same cover where the OT sensor is located, but up at the top....a ⅛" brass NPT plug is there. If it is removed and a hose barb is installed, you can run a tube with the wiring cable up to the dash for installation of an "after market" water pressure gauge. Max pressure is 20 psig, so a 0-30 or 0-50 psi gauge should suffice.

 

[MonkeyBird747]

Texasmark, that is incredibly helpful. I'm going to print it out and take it to the boat with me to follow along.

I do have the 4 pin connector at the controls that isn't connected to anything, but not the plug that mates with it. I can splice in though.

I have the brown wire in the back coming from the water jacket, and is not connected to the main harness. Hard to describe, but there is a matching brown wire sort of pigtailed into the main 8-pin wire harness back at the engine. Sounds like I just need to connect these two together.

I don't have a horn under the dash, and pretty sure not in the controls since I had those apart recenty. I'll pick one of these as well up so I can test things out.

Sounds like I need a tach, trim position gauge, and warning horn. I can live without speedo and just go with GPS value. I don't have a lot of space at the center console for a bunch of gauges. How important is the water pressure indication? There is a hose bib installed already, but I was planning on removing it and installing a plug instead.

Thanks,

MB

 

[Texasmark]

There are several wires in the engine when you look at what can be connected to the alarm pin. Just plug into one of the pigtails to get your warning signals to the tan/light blue stripe wire in the harness. The connectors are "Bayonet" style.

The alarm is only about the size of a US Silver dollar , about ⅜" thick and comes with a strap, like a zip tie strap to attach it to the bundle of wires under the dash...

Water pressure tube (seems to be popular for off shore boating) or electrical engine temperature (what I use) with a temp sending unit in that ⅛" port are good ideas for when you need them. Your owner's manual gives you the numbers, like on that engine 5# give or take and 15# at WOT come to mind. I chose temp because i can watch my thermostat opening and closing...only problem I had with OT issues over the years. Off shore folks tell me that as the impeller wears, the pressure drops from normal and it is an early indication that it's time for the impeller in the water pump to be changed.

Pigtailing off the connector is fine. I gave you the colors of the functions, you can use what you want for interconnecting...no big voltage or current demand there.

Not all engines have trim position sensors on the engine...might check first. I never looked at where mine is located but I think if you tilt the engine up to 20* or so and look at the engine part of the transom bracket-engine interface you will see it mounted on the side of that bracket. This is the first engine in over 60 years of boating that I had an engine with a sending unit......they are a must on I/O installations where you can't see the outdrive from the helm.

Need more ask.

 

[MonkeyBird747]

Thanks again. I'll look for the trim sending unit before I order a gauge. It would be a nicety, but if it isn't already there I won't bother with trying to install one. I'm just going to fishing inland lakes around the area, and no tourney or big water stuff. You've also reminded me to check my thermostat while I'm at all this. I'll be hands on with the boat this weekend and might have some follow up questions afterwards.

 

[Texasmark]

Opening temp is stamped on the bottom. Slip a thread under the movable plate and get a pot of water on the stove and a candy thermometer. Suspend the stat is the water with the string. When the opening temp is reached, +. 5* for a number the stat should drop to the bottom. Also check the poppet valve adjacent to it for ease of operation and corrosion. Both are under the upper left bulge, on top of the water jacket cover on the rear of the block.

 

[MonkeyBird747]

Ok, so I got most everything sorted out today. I wired the remote trim switch. Easy peasy. I drained the oil tank and turned on the key. Low an behold there is an alarm in the throttle quadrant. Filled the tank up while it was on and it turned off about a quarter tank.

The temp sender (brown/blue stripe) wire it tied in with the low oil level wire. So it seems a common alarm for both? So right now my solid brown wire is unused. Haven’t tested the thermostat yet. It’s on the list.