How does Fuel/Oil/Paddle Assembly Harness work with MercMonitor???
So, the Fuel/Oil/Paddle Assembly harness (859743T2) was not attached to anything on the 2003 Optimax Powerhead. I noticed it when I was going to attached the black speedo tube to the digital sensor. Figured I'd better ask before completing MercMonitor install.
Does this harness need to be attached and/or does it work in conjunction with the MercMonitor blue CAN data cable?
Thoughts?
dh
Last edited by darleyhavidson; 12-09-2018 at 08:20 AM.
The harness connects to the fuel tank sender and oil tank sender, if equipped. The harness must be installed EXACTLY as directed in the instructions, or damage will occur.
I don't have any installation instructions for the harness. It was installed on the powerhead when I got the boat. Truth be told, I didn't know the harness was there until I removed the lower cowl panel. Where can I start looking for the fuel and oil tank sender wiring at the powerhead? And installation instructions?Originally Posted by Savage
Last edited by darleyhavidson; 12-09-2018 at 08:44 AM.
Contact Mercury Marine...…...or goggle "Mercury fuel oil harness instructions"
Look at your remote oil tank to see if there are any wires connected to it or a place for wires to attach. If yes to either, then you have the float assembly, if no, then you don't. The fuel sender is already attached to your tank, you cannot have analog fuel indication AND Smartcraft off the same sending unit, it's one or the other. When I installed my Mercmonitor including the fuel/oil/paddle harness and oil level float assy, I left the OE analog fuel sender as is.
_______
Phil
'09 Hewescraft ProV
'09 150 Optimax
I do have a place for wires to attach to the remote oil tank cap as it does have a float assembly (but no wires are currently attached). As far as the fuel sender, I guess I was trying to find which color wires are at the powerhead that I need to tap into to attach the harness to eliminate the OE analog and use the SmartCraft connection.
The Google Harness install instructions I have found don't match the wiring color coding I show at the powerhead, so I am going to have to map out what wires are connected and which ones are not and report back.
dh
Okay, I tried to attach a picture but after an hour of trying reduce it to fit, I had to move on (side note: this is the only forum out of 10 that I frequent that I cannot easily upload photos).
At any rate, the harness is connect to the powerhead. It has three separate wires that are not part of the connector. (1) Black, (1) Yellow, and (1) Light Blue
From what I have read the Black and Yellow wires are for the digital trim sendor. These particular wires have had the ends heat shrinked and are not being used.
The light blue wire is splice into (2) purple/yellow coded wires. The purple/yellow wires go to the digital speed sensor that is below the starter.
The blue wire is not connected to anything, which is fine as I use the GPS on my graph for speed. But I will be disconnecting the black speedo tube and connecting it to the digital speed sensor as I am removing the factory speedometer and placing the MercMonitor in its place.
I have not located the Lt Blue/Black wire (Remote Oil Tank) or the Pink/Black wire (Fuel Sending Unit) and their corresponding Black/Orange wires. So not sure how to hook up any of these with the harness (or if its even needed).
I am sure this is clear as mud, but any insight any of you can provide would be helpful.
dh
You need to be extremely cautious in what you are attempting, a simple error and you could end up with damaged ECM
Thank You Leon Pugh
I am not attempting anything. I am trying to obtain guidance and clarification. My original post I posed the following question:
Does this harness need to be attached and/or does it work in conjunction with the MercMonitor blue CAN data cable?
So, do I leave the harness alone? Or do I need to make certain mods so it doesn't impede the function of the MercMonitor [or unintentionally omit other functions (analog or digital)]?
dh
Last edited by darleyhavidson; 12-09-2018 at 03:57 PM.
It has been a while since I did one and I hope I remember properly. I have only done these installations with just a Mercmonitor AND the harness.
The fuel/PW harnesses that I have installed have their own connection plug under the cowling on the right side below the starter.
USN Retired
2020 Basscat Caracal
2020 Mercury 225 ProXS 4s
The Mercmonitor can work without the fuel/oil harness .......just no fuel or oil inputs will be given.
Yep, that is where mine is connected. And then there is about 4 foot of harness that would go to a paddlewheel. And there is a black, yellow and light blue wires that come out of the harness (adjacent to the connector).
I left it connected and cleaned up the wiring a bit.
That's what I was confused about as I could not tell how the harness even affected the fuel or oil inputs. No color coded wires within the harness matched up with the fuel/oil sending unit wiring. Still not sure how it works. I left the harness connected, the only negative is cramming the 4 foot of additional harness (that I can't use) in the lower cowling area.
dh
It may not tell you how much fuel or oil you have, but it will tell you how much fuel you’re burning in gallons an hour and how much fuel you’ve used.
Joe Perez
Boatless white trash
DH you don't need the harness to know fuel used that is already supplied to Mercmonitor from the PCM via blue CAN cable.
The Fuel/Oil/Paddle harness only provides the following:
-- remote oil tank level (float assy required)
-- paddle wheel speed (paddle wheel required) OR sea temp (sender required)
-- digital fuel level on Mercmonitor MUST REMOVE ANALOG FUEL CONNECTION AT SENDING UNIT
This is what lpugh was referring to, if you DON'T do this right you CAN take out the PCM by backfeeding harmful voltage to the PCM.
I installed this harness and oil float assembly several years ago because I wanted remote tank level on my Mercmonitor. No need for paddle wheel speed with GPS and since Mercmonitor reads fuel used from PCM I didn't need to see tank fuel level as my analog gauge was adequate for a "visual indicator". If desired, you can replace your analog fuel gauge with a System Link gauge connected to the Mercmonitor.
The harness has nothing whatsoever to do with digital trim and I have no clue what a digital speed sensor is and am unaware of any such sensor on the powerhead.
You have a PM.
_______
Phil
'09 Hewescraft ProV
'09 150 Optimax
Thanks for the information and PM. Unfortunately, I was given bad information that led me to start this thread. The advice given in the posts above make sense if I actually had the fuel/oil/paddlewheel harness.DH you don't need the harness to know fuel used that is already supplied to Mercmonitor from the PCM via blue CAN cable.
The Fuel/Oil/Paddle harness only provides the following:
-- remote oil tank level (float assy required)
-- paddle wheel speed (paddle wheel required) OR sea temp (sender required)
-- digital fuel level on Mercmonitor MUST REMOVE ANALOG FUEL CONNECTION AT SENDING UNIT
This is what lpugh was referring to, if you DON'T do this right you CAN take out the PCM by backfeeding harmful voltage to the PCM.
I installed this harness and oil float assembly several years ago because I wanted remote tank level on my Mercmonitor. No need for paddle wheel speed with GPS and since Mercmonitor reads fuel used from PCM I didn't need to see tank fuel level as my analog gauge was adequate for a "visual indicator". If desired, you can replace your analog fuel gauge with a System Link gauge connected to the Mercmonitor.
The harness has nothing whatsoever to do with digital trim and I have no clue what a digital speed sensor is and am unaware of any such sensor on the powerhead.
You have a PM.
I do not have this harness, it is simply the Smartcraft harness (that a fuel/oil/paddlewheel harness would plug into).
So, my apologies, but I got burned by some erroneous info I found on the intraweb.
Thanks to all that provided assistance, I will do better in the future as I strive to learn more about this motor.
dh
Savage,
My apologies. I stand corrected.
Joe Perez
Boatless white trash
_______
Phil
'09 Hewescraft ProV
'09 150 Optimax
Please review the Forum Announcements and ALWAYS include the Required Info with your posts. Thanks!
Fuel/Oil harness is OPTIONAL. That means it is not required to make a Smartcraft Instrument "function".
In order to utilize fuel LEVELS, you must have the Fuel/Oil Harness, which connects to the Engine's wiring harness (directly). Nothing whatsoever to do with a Can-P Data Cable.
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Still consider myself a "Marine Apprentice" after 47 years (learn something new every day).
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Appreciate the information.Please review the Forum Announcements and ALWAYS include the Required Info with your posts. Thanks!
Fuel/Oil harness is OPTIONAL. That means it is not required to make a Smartcraft Instrument "function".
In order to utilize fuel LEVELS, you must have the Fuel/Oil Harness, which connects to the Engine's wiring harness (directly). Nothing whatsoever to do with a Can-P Data Cable.
Is the info in my signature block not suitable "Required Info"?
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