Mercury Smartcraft.

Nasher · 20 July 2021, 10:32

I have to confess that due to many and varied reasons the 225 Optimax I purchased over a year ago now is still sat on a pallet in my storage container rather that mounted and running on the Transom of my RIB. Although I have done a lot of work to the boat in the meantime and still have some to go.
But I’m getting there, and gathering all the parts I need.

I jumped into the purchase without knowing anything about the Smartcraft system, and unfortunately haven’t been helped by the guy who sold me the engine with a rigging package that just shows his ignorance of the system rather than any actual knowledge.
There are also other ‘Issues’ with the engine that I’ve found already, and although very easily sorted they are a little annoying.

The engine is a 2003 Mercury 225XL Optimax.
Smartcraft wise it came with:
long Blue cable -84-879981 Rev B - 06-25-2002.
A rough looking Speedo – 79-879 899 V:2.21 dated 28/01.
And the instruction “Plug the Blue cable into the Speedo and get the revs on the LCD screen”.

I’ve done some homework, made some decisions about what I want, and now think I understand what I need to rig the system to my requirements.
But am struggling with some of the last details, I’ve also not been able to establish for certain if various revision versions of parts will work with each other.

My plan is to go with:

Blue cable
Junction Box
Junction box to revcounter cable
Revcounter
Junction box to Speedo cable
Speedo

The Blue Cable I know is compatible with the engine, so that’s OK.
I also have a junction box that I know is compatible, so again that’s good.

I did initially not want a Speedo at all, but some of the smartcraft functions can’t be displayed on the Revcounter.

I’m going to initially go with the Engine Pitot tube speed sensor as it’s there and I have all new parts for the tube itself, and it might be fun at times to compare speed through the water to speed over ground from my GPS like a yachtie.
It may be useful to help establish what current is running for the Divers when searching on the depth sounder for a reef.
But if it doesn’t work properly or isn’t accurate I’ll NMEA the speed to the Speedo from my GPS instead.
I do know by the way that I’m more likely to end up with the NMEA link.

Nasher · 20 July 2021, 10:33

I now have very good condition matching Revcounter and Speedo.
Revcounter 79-889222 A13, SW V4.00 - dated 29/07
Speedometer 79-889223 A13, SW V4.00 - dated 27/07

Question 1 is, will the V4.00 2007 Instruments work with the 2003 engine?
I can’t find a reason why not online.

Revcounter Cable.
I have 3 available to me:
84-89979A1 Rev B – 10-07-2002
84-879979A1 Rev C – 04-11-2007
8M0031688 Rev C – 08-03-2012

The first two appear identical apart from some differences in cable tie position etc.
Certainly the pin-outs on the various connectors are identical.

The third, later one, has identical pin-outs etc, apart from the Ground connection to the revcounter is a separate cable to ‘Vessel Ground’ rather than coming from the junction box.

Question 2, Can I use the later 2012 cable with the revcounter?
I can’t see a reason why not, and would like to if Mercury have identified the Ground coming direct from the vessel being a better option.

Speedo cable.
I have one, purchased with some other parts, 8M0055041 Rev A – 05-29-2014.
But it’s marked ‘ Use with Rev 6 or higher gauges’ so isn’t any good to me.

I believe I need an 84-879978A1, but can only find them for sale used on US EBAY.

Question 3, can anyone confirm that part number? And if there are any revisions I should be aware of that will cause issues with the 2003 engine and 2007 Speedo?

Question 4, do I really need an External Temperature Sender?
Does it effect anything else, or is it just to display in the menu on the Speedo.

Many thanks for any help anyone can be.

Thanks

Nasher.

Iankristy · 20 July 2021, 15:00

Quote:

Originally Posted by Nasher

I now have very good condition matching Revcounter and Speedo.
Revcounter 79-889222 A13, SW V4.00 - dated 29/07
Speedometer 79-889223 A13, SW V4.00 - dated 27/07

Question 1 is, will the V4.00 2007 Instruments work with the 2003 engine?
I can’t find a reason why not online.

Revcounter Cable.
I have 3 available to me:
84-89979A1 Rev B – 10-07-2002
84-879979A1 Rev C – 04-11-2007
8M0031688 Rev C – 08-03-2012

The first two appear identical apart from some differences in cable tie position etc.
Certainly the pin-outs on the various connectors are identical.

The third, later one, has identical pin-outs etc, apart from the Ground connection to the revcounter is a separate cable to ‘Vessel Ground’ rather than coming from the junction box.

Question 2, Can I use the later 2012 cable with the revcounter?
I can’t see a reason why not, and would like to if Mercury have identified the Ground coming direct from the vessel being a better option.

Speedo cable.
I have one, purchased with some other parts, 8M0055041 Rev A – 05-29-2014.
But it’s marked ‘ Use with Rev 6 or higher gauges’ so isn’t any good to me.

I believe I need an 84-879978A1, but can only find them for sale used on US EBAY.

Question 3, can anyone confirm that part number? And if there are any revisions I should be aware of that will cause issues with the 2003 engine and 2007 Speedo?

Question 4, do I really need an External Temperature Sender?
Does it effect anything else, or is it just to display in the menu on the Speedo.

Many thanks for any help anyone can be.

Thanks

Nasher.

Mercury outboard owners on FB pretty active and can be helpful [emoji4]

neil.mccrirrick · 20 July 2021, 18:36

Can’t help the part numbers but I turned off the external sensor on mine and all is fine. It’s not needed unless you are operating in freezing water or so I’m told

Nasher · 20 July 2021, 22:57

Thanks Neil

Sorry IanKristy, assuming you mean Facebook by FB, it would take a lot more than these questions for me to consider going anywhere near it.

Nasher.

Nasher · 21 July 2021, 10:06

The Service Bulletin I've found online(below) confirms that as my Revcounter and speedo are V4 Software revision I should be using the later cables with the separate Ground connection.

Which confirms I can use the Revcounter Cable I want to, but still leaves me without a Speedo cable.

So I'm actually looking for an 84-8M0031689 cable/Harness.

Although I still don't know if my 2007 V4 Gauges will work with the 2003 engine!

Nasher.

Waterman · 22 July 2021, 07:50

The smart craft/optimax wiring looms are a nightmare….. I had to change entire engine wiring loom previously and there was something like 6 or 7 versions of it within a two year period with very slight variations…..
Rob at black dog marine (think turbodiesel on here?) was very helpful at the time and sourced the correct one for my setup [emoji1303]

Nasher · 22 July 2021, 08:01

Thanks Waterman.

Yep, like you I've found the part numbers and revisions are a bit of a nightmare, hence my questions.

Turbodiesel is a very helpful guy, and I did think of him, but didn't really want to contact him directly just to ask advice when his business has no chance of making a sale from it.

Nasher.

Searider · 22 July 2021, 09:53

Later gauges wil work with your engine. I've had many different gauges with my 2001 opti and they were all fine.
The external temp sensor I thing is part of the mapping but probably not critical.

Nasher · 22 July 2021, 10:20

Thanks Searider

Having worked in Marine and Aviation Electronics for years now I do understand that an up-issue to a Cable Assembly can be significant, or just a 2mm movement in the position of a cable tie.

Ref the Air Temp sensor, I was trying to avoid buying one, but the cheapest cable assembly I could find for sale - US EBAY, came with one included, so I might as well plug it in.

Nasher.

Searider · 22 July 2021, 10:32

Quote:

Originally Posted by Nasher

Thanks Searider

Having worked in Marine and Aviation Electronics for years now I do understand that an up-issue to a Cable Assembly can be significant, or just a 2mm movement in the position of a cable tie.

Ref the Air Temp sensor, I was trying to avoid buying one, but the cheapest cable assembly I could find for sale - US EBAY, came with one included, so I might as well plug it in.

Nasher.

I've got a box of random smartcraft stuff in the garage - but can't remember if theres a temp sensor there or not.