Mercury Outboard Gauge Wiring - HOW TO INSTALL

[@frankschannel2642]

Helpful!!! Thank you.

[@tomspontoons]

Great! Happy to help!

[@bthompson101202]

I was so confused on how to wire things up. I just ordered that harness yesterday and even though i will be installing Vessel View Mobile i want to have my physical gauges also. I have ordered my 50hp elpt command thrust and i cannot wait to get it on my 18ft pontoon. Always enjoy your videos. Thank you for explaining things so simple for everyone can understand.

[@tomspontoons]

Thank you for watching. Glad this was helpful. The harness makes it SO MUCH better to install a set of gauges because it gives you as close to a plug and play scenario as possible. You'll still have to run some wires across from gauge to gauge for power and ground, but it's definitely less of a headache!

[@KashIrons]

Great video, thank you for taking the time to go through it and help people understand how it all works. I am redoing and old boat and it was an absolute rats nest behind the gauges and video's like this help give some confidence to clean it all up.

[@tomspontoons]

Thanks! It's always so great for us to hear when we're helping folks feel confident that they can complete these types of projects at home on their own boats. We like to try to put entertaining stuff out there, but the bulk of what we do is how-to...glad it's helping!

[@timdare0831]

Fantastic job. Very interesting. I'm in the process of doing mine as well.

[@tomspontoons]

Thanks for watching! Best of luck with your project.

[@karlzink3708]

I have a 2005 4 Stroke EFI Mercury. I believe the connection to the motor is 8 pin (plus 4 loose wires) vs the 14 i assume in this video. I can't find a wiring diagram on what the 8 pins go to. It currently doesn't have any gauges but I'm redoing the boat including floor. I ideally want speedometer and tachometer to work and assume that is in the 8 pin harness? Should I get an 8 pin to 14 pin pigtail and run a new 14 pin harness with the gauge harness? I unfortunately am not near the boat so I'm not exactly sure what each end looks like on the current harness. Thanks again. Great videos.

[@tomspontoons]

Typically on the 8-pin connector (and even the 14 pin) there's a gauge harness lead that comes off the main harness. A gauge harness (separate part) will then plug in. On the 8-pin it's a small black half circle plug with a purple, black, and gray wire. It might also have a tan or brown wire in there too. That allows you to pre-wire your gauges and then plug right in. If it's a side mount control box (attaches to your railing) the gauge harness plug will be coming out of the back of the control box and you may need to lengthen the leads on the gauge harness itself to go back under the floor and up to the console. On a binnacle style the plug should be up near the key switch under the console. No need to do an adapter for the harness, and honestly it wouldn't do exactly what you need it to anyway. Should be able to get it done without changing anything out, just need that gauge harness (or to splice into the main harness, but I don't recommend that for long-term success). Hope this helps!

[@kingfish3066]

The absolute best gauge install and wire tutorial on KZbin PERIOD!!!! Your timing for this is spot on as I was looking for some help because I'm in the middle of a full restoration on my boat and planned on knocking this out tomorrow, thanks Tom.

[@tomspontoons]

Thanks so much! Gotta love when it helps someone out because that’s what I’m here to do! We have a couple other videos on gauge wiring too with different motors and gauge scenarios so take a peek in case you need additional info!

[@kingfish3066]

@@tomspontoons yes I've seen the others but this one I could see everything you were doing really well

[@tomspontoons]

@@kingfish3066 good to know! We will keep trying to do just that!

[@mikepatterson3717]

Thanks!

[@tomspontoons]

Thanks so much for the contribution!! It all adds up to help cover the time and effort that goes into creating content and staying involved with comments and questions. Glad this video was helpful for you and your project!

[@Rzuspann]

You’re amazing man! Thanks

[@tomspontoons]

Glad it was helpful! Thanks for watching

[@Timbuctoo]

My Merc Optimax has a Smart Craft cable the runs from the controller to the Tacho. Would it be better to use the smart craft tacho, or get the harness you have and use the non-Merc tacho? I tried to hook up my Smart Craft tacho the other day and no power to the gauge.

[@tomspontoons]

If you've got no power to the smartcraft gauge I would be nervous buying another smartcraft gauge in the event that there's an electrical issue (more likely your gauge is bad, but you never know). I pretty much exclusively rig with that gauge harness and analog gauges because most of what I'm working on takes multiple gauges and needs a whole new dash of gauges.

[@676Matty]

Thanks Tom! Still varnishing our dash panels but soon, very soon,,, I will tackle the birds nest that is the curent (see what I did there?) wiring mess and convert it over to our new set up.

[@tomspontoons]

You'll be so happy once your hard word is finished and you're out on that "new" boat enjoying it all. If reusing all the old electrical and you're unsure at all, just label both ends of each item as you cut it out of the old stuff. Keep "tooning" in for more content too!

[@lejendmerchant6472]

I notice you’re using the wiring harness that is coming from the control box to power these gauges. So could you use the same power (red or purple) to power to the accessories panel (the rocker switches) for the horn, nav lights, ect? Or do I need to run a whole new power/ground cables directly from the battery to the switch panel for accessories?

[@tomspontoons]

You could possibly power a stereo or a fish finder off of the ignition power, but I would ALWAYS recommend running your accessories on their own power and ground as they will take more draw and should be a beefier power and ground wire to carry the load for all of those accessories that might be used at the same time. Your ignition wire is usually only 14 or 16 gauge which is fine to trigger the starter and power some gauges, but not made to power all your boat's accessories. You'll see me reference the Pontoon Stuff wiring harness constantly for those items like lighting, stereo, fish finders, bilge pumps, etc. Hope this helps!

[@Bamaoutdoors]

Do you have any videos on installing a hour meter for a 90 Mercury? I just bought a 2014 Sun Tracker and would love to put one on it.

[@tomspontoons]

Your best bet would be to install a Vessel View which hooks right up and bluetooth connects to your phone giving you all of your live engine stats and hours. It's about $250 and installs in minutes. I've got details on it in my video for installing a new Mercury outboard.

[@anthonybass7851]

Great video Tom. Do you have a video on how to wire Suzuki gauges? Thanks

[@tomspontoons]

I don’t, but it’s extremely similar. Some of the newer Suzuki gauges are simply plug and play into the back of the gauge from the harness making it even simpler.

[@anthonybass7851]

@@tomspontoons Thanks for the feedback. I went for it and bought a new 200 Suzuki for my tritoon build . Gauges are on order and should be here tomorrow. I was hoping they would be plug and play. You’re KZbin videos have gave me the confidence to take on this project. Keep up the good work!!

[@tomspontoons]

@@anthonybass7851 great choice!! I had a couple little goofy things with the digital gauge I have on my boat, but it was fairly simple to resolve.

[@diivan4341]

Awesome video! U just got a new subscriber 👍

[@tomspontoons]

Thank you for watching AND subscribing!! Hopefully we’ve got lots of helpful stuff for you!

[@diivan4341]

@@tomspontoons just bought a new suzuki DF90 and after your videos i will have no problems doing it myself! 😀👌

[@tomspontoons]

@@diivan4341 great choice! I love my DF200! I am building a river boat in the near future that’s getting a DF140 with a jet. I’m sure I’ll share a video of the maintenance on that too.

[@diivan4341]

@@tomspontoons Oh nice! Cant wait 👍

[@tomspontoons]

@@diivan4341 Trust me, I can't wait either! I'll make a video documenting the project. Should be a fun one!

[@SteveWalton-g7s]

I have a new controller with a different plug for the gauges. It's a round 5 PIN connector that doesn't fit the harness I purchased (the one you recommended). How do I connect them?

[@tomspontoons]

There’s a separate gauge harness for that plug. You could return the more modern style and purchase that older style. Otherwise you’d have to cut that 5 pin round connector off your harness and then cut and splice into the modern harness. The wire colors are still the same.

[@SteveWalton-g7s]

@@tomspontoons Any idea what harness for that plug is needed to match up?

[@SteveWalton-g7s]

@@tomspontoons Or what plug by name or part number will match the controller harness?

[@tomspontoons]

@@SteveWalton-g7s google search “Mercury Gauge Harness” and make sure it looks like the same plug you have. Or there’s always Amazon! a.co/d/32K3DuM

[@SteveWalton-g7s]

Perfect

[@metzdavis7208]

Awesome video.

[@tomspontoons]

Thanks! Hope it helped!

[@עדיאלראופר]

Hi Like your video! Is the harness came labled as shown on the video? If so can you please send a link for boat the harness and gages Tank you

[@tomspontoons]

Thanks for watching! Like in this video I often have to make my own harness from scratch for the gauges, but your local Mercury parts dealer can get you the gauge harness that attaches from the gauges into the ignition harness. I simply buy them from my local Mercury parts dealer.

[@davidcobb4527]

Hey Tom, is it possible to piggy back the stereo off of the key-on wire from the back of the gauges? Would like to have the stereo turn on with the turn of the key. Cheers pal.

[@tomspontoons]

You absolutely could do that, just make sure you've got a fuse in line from the gauge to the stereo. Just remember you will have key on power to the motor which will draw extra power for the ECM to be on in the event you're listening to the radio without the motor running. I would really only recommend it if you ONLY listen to music with the motor running. I prefer to put the radio on its own accessory switch.

[@davidcobb4527]

@@tomspontoons thanks Tom. Then that’s what I’ll do. 👍🏼

[@rogeliorodriguez7350]

I have 2 Multifuction faria with 3 on each. How can I figure out the wires.

[@tomspontoons]

I haven't tackled that sort of gauge yet. Faria has solid customer support and lots of documents for help/instructions. If I ever install those gauges I'll definitely make a video covering it.

[@Jcnell9]

Great video going to start doing mine thanks what size wire do you recommend

[@tomspontoons]

Thanks! Glad it’s helpful. I use 16 gauge on everything for gauges.

[@Jcnell9]

Thank any special wire tinned copper or just regular wire

[@Jcnell9]

@@tomspontoons Thanks for info any special wire tinned copper or just regular wire

[@tomspontoons]

@@Jcnell9 Always tinned copper marine grade if at all possible!!

[@stevenhendrickson2910]

What are the 3 extra wires (red white and blue) that hang from the end of the gauge harness used for? It looks like the blue wire had once been used on my boat but was disconnected.

[@tomspontoons]

I’m not 100% sure which wires you’re mentioning. Is it coming off the gauge harness or elsewhere on the ignition harness?

[@stevenhendrickson2910]

​@tomspontoons sorry for not being concise. At timestamp 3:15 you have the connector in your hand along with the red white and blue wires I mentioned None of the 3 have a tag on them to identify them and I can't find anything online as to what they are for.

[@tomspontoons]

I reached out to my friend who is a Mercury tech and he said the service manual doesn’t even tell what they’re for. Pretty odd, but I guess you’d have to get with Mercury to find out!! I’m guessing they tie into the smart craft gauges or are some sort of accessory power supply.

[@precisionsmallenginerepair7572]

I have a 2012 Mercury 40hp 4stroke on a Bass Tracker. The boat has never had a gauge of any description installed in the dash since new. On that engine, should there be a plug in the wiring harness for gauges like the one in this video?

[@tomspontoons]

That motor should have a harness with a simple plug in under the helm that’s already labeled gauges. Same harness that hooks to the key switch and shift/throttle, and runs back to the motor. You could splice into those gray, purple, and black wires for powering gauges and supplying the tach signal. The best way would be to buy the gauge harness that plugs into that gauge lead. It’s a Mercury OEM part and costs only about $35-$40

[@robbienardelli4272]

Tom, is a tach / rpm gauge necessary? or can you get away with not putting one on the gauge panel?

[@tomspontoons]

You can 100% go without a tach. Your horn/alarm on most newer motors is built into the key switch or iginition harness. It would go off for temperature or oil related alarms. The risk of no tach is not knowing if you have the proper propeller installed for your boat. If you run too high of RPMs you can damage the motor (especially if no rev limiter is in place) and if you’re running too low of RPMs at wide open throttle you can damage the motor too. The tach allows for a sweet spot to be found. A temporary tach could be rigged to the motor to test your wide open throttle RPMs too though. I will cover all that in a propeller segment of the whiteboard coffee chats!

[@robbienardelli4272]

@@tomspontoons thanks Tom, appreciate the in depth response...u da man

[@tomspontoons]

@@robbienardelli4272 happy to help!

[@BuenoToob]

I've just rebuilt my pontoon and am wondering what gauges you find unnecessary (i.e. which gauges are important to have). I have a 60hp Mercury Bigfoot four stroke, so we just cruise like a bunch of old people and enjoy the lake. From a safety standpoint I think fuel gauge, trim gauge, but not sure I need tachometer, temp, or mph gauges (or do I?). Looking for insight here. Any others I should consider? (Of course, I'm thinking I can always add more later, if needed?) Thanks

[@tomspontoons]

Great question, thanks! I personally like to have a tach, fuel, and volt gauge on my projects. The tach will give information for making sure the prop is correct and that you're not over-loading the motor when running the engine harder. Keep in mind that the trim gauge only shows the trim level. Once beyond a few degrees of trim it stops reading...so it doesn't really tell you if the motor is tilted way up or down. I rarely install trim gauges because a lot of times there are additional parts and even a sending unit that must be installed on the motor to indicate trim. So for me it's usually fuel, tach, and voltage. And yes, you can always add more later.

[@sonofslade8235]

As far as a fuel guage, what if you're just running two common 12 gal plastic fuel tanks?

[@dianabartram4019]

my hubby knows nothing about wiring and is wondering what color wire coming from mercury 115 motor to console goes to the heat sensor and also what color to the speed

[@tomspontoons]

Definitely double check, But my chart says “tan” is the temperature light. The speedometer will be powered from the gauge harness. There’s no indicator for speed from the motor’s ignition harness. Some are driven by GPS while others have a tube that connects to the motor or a sensor that drives water pressure to indicate speed (less accurate).

[@tritownnow]

Again we’ll done Tom! Quick question, is the wiring harness from the engine to the console one complete part number or is it different harnesses that you had to run independently? You showed the wiring at the console, is the other end by the engine one large multiple PIN plug in?

[@tomspontoons]

The gauge harness is a separate part number, that’s the part bag I showed in the video. The main ignition harness is a different part and runs from the engine to the console. I believe it’s Mercury part number 896537K20, but it changes and supersedes often so double check. There are also shorter and longer harness options available. This main ignition harness will include a key switch too. It hooks into the motor on the round 14 pin side, and then plugs into your trim/tilt and neutral safety of the shift/throttle box (binnacle style), and has the plug in for the gauge harness to plug into as I did in this video under the console.

[@bretsherk]

Hi, Question: I have a 2015 Mercury 4 stroke Tiller (Big Tiller arm) ... So I am trying to hook up gauges ( on a Lund Pro Guide). I opened the cowl and there are 4 wires (green , gray, blue and purple). Can you help me with what goes where? My research shows purple to Key power, Gray to tach.. GREEN ??? BLUE??? ... perhaps you have a video showing this? Thanks! Bret

[@tomspontoons]

I don’t have a video showing tying gauges into a tiller motor. For that new of a Mercury I’d think there should be some harnesses or a hookup for a gauge harness under the hood, rather than having to splice in. Generally on a Merc the purple is key on power, gray is tach, and green/blue would be down/up for trim/tilt. I would reach out to a local Mercury dealer for further instruction. I haven’t worked on that scenario before!

[@JohnWisconsin]

Any thought on why my (old, 80s) gauges don't read correctly? For ex: the gas is roughly 0-3/4 and the trim is 0- mid gauge (instead of transitioning from trim to tilt in the different colored zone)? Would it be poor conductivity (clean the wiring or even replace) or the senders or the gauges? It's new to me and not sure if there's any fine tuning settings or ?

[@tomspontoons]

I’m not totally sure why, but it seems like gauges are just the most finicky part of boats. It seems like most of my customers have gauges on their boats that don’t work, or don’t read properly. Best bet is a clean start with new gauges and wiring to them. The trim gauge is the most temperamental in my opinion. Some read backwards/upside down, some motors need an extra kit to add a sending unit on the motor, etc. However, trim gauges ONLY read the trim level of the motor…so after the few degrees of trim they will be maxed out, and the rest of the way up (the tilt portion) will stay at the top of the trim range.

[@unsaltedlife5998]

I got my toon to the point of installing the new console gages put in and steering wheel too now it sets in my garage as the temperature is -1 with a wind chill of minus 20 , So it’s a great time to catch up on your videos merry Christmas and thanks for sharing your knowledge. Question where did you find the plastic for the gauges to mount in.

[@tomspontoons]

We’re feeling that super chill right now too! Hopefully we’ve got everything covered that you need to see for your project. If not please let me know what you’d like to see covered! That marine board came from Great Lakes Skipper, but it was SUPER hard to work with compared to other types. I just built another panel out of marine grade plastic from Amazon and it worked great and was easier to cut and drill into. Search “marine starboard” and you’ll find lots of options, colors, sizes, and thicknesses. Thanks for watching!! Merry Christmas!

[@unsaltedlife5998]

@@tomspontoons thanks, My pontoon used to be my dock I bought it to use as a dock and after watching your Chanel decided to rebuild it.

[@tomspontoons]

How cool is that! You’ll love having a functioning place to hang out, cruise the lake, and enjoy being on the water…it’ll be well worth the work put in!

[@natefonseka]

if you ever get to it @tomspontoons can you do a video of rigging a battery pack to rear under-seat using pontoonstuff? My toons rear seating is absolutely shot, and need to be replaced.

[@tomspontoons]

Absolutely! We generally install them under the sundecks, but we do put them under rear seats too. I run a 2" hole through the seat and deck, and then a rigging boot to protect the cables and prevent water from coming up into the seat from waves and such. Those rigging boots can be found at Pontoon Stuff. Lastly, I either install a battery box or other battery tray to keep everything in place. I've installed them under 28" benches, 38" benches, and 28" corners too like that.

[@reynoldsautorepair173]

Where are you located

[@tomspontoons]

Grand Rapids, Michigan

[@dude5576]

i couldnt crinp my wires tight

[@tomspontoons]

One thing in my toolbox I definitely don’t go cheap on are my wire crimping pliers! Also, make sure you’re using the correct size terminals and splices for the wire diameter you’re running.

[@dude5576]

What kind of stripper do u recommend

[@tomspontoons]

I’ve had great luck with Klein brand wire tools!

[@GaryJones-gm4fs]

❤​@@tomspontoons❤❤❤❤❤❤

[@Striperguy_909]

Need better tools . Other than that great video!

[@tomspontoons]

To each their own! Mine have lasted me working 5 days a week on boats for over 3 years. Very rarely do I have to spend money on tools!

[@bretsherk]

Sorry I can add photos if needed. or email