How to add electric start to a small outboard motor, DIY electric start on a Mercury outboard motor

[@bobsbarnworkshop]

Ring gear part number : 43-99301 just search for "Mercury outboard ring gear 43-99301" and you'll get numerous hits. held to the flywheel with 4 M5x13 bolts. The starter motor is part number: 50-90983A1,held on with 2 M8X55 bolts, the fast Idle/choke lever is part number: 42515A1. All the above parts were just searched and found multiple suppliers. Hope this helps you out!

[@jjohnston6645]

I have a 94 25 hp Mercury, yup I need to get me a ring gear and get started on this project, I'm getting to dang old jerking on the pull rope.

[@vincegallegos9790]

Oh wow, my first motor was a 8 hsp mercury 1988. Wished I had this cool setup on mine, just the pull start is all I’ve ever owned back in the day. Never failed me though. 😅 good job. 😊

[@bobsbarnworkshop]

I was an electrical contractor for most of the 70’s, then EE for another 35, so electrical stuff is my gig! I’m glad you enjoyed the video! Thanks for watching!

[@thomasstubbs2624]

Thanks for the video. I am doing the electric conversion now. I already have the starter installed now I'm just trying to determine the wiring. I like your idea of just putting the solenoid in the battery box and only having to run the #6 wires to the motor. I may do the same or permanently mount another small waterproof box high on the transom since my battery (deep cycle for the trolling motor) is taking up most of the battery box. I may also look into adding a charge coil as well.

[@bobsbarnworkshop]

I did a later video adding a charging coil to my motor which required me to run a separate wire from the rectifier diode back to the battery box, but it works fine!~ Good luck!

[@johncooper6246]

Very cool. I'm guessing the (LED) pilot lights have internal 680 ohm 1/4 watt drop resistors as they operate at +/- 2 volts. Mine didn't having to install them manually. No biggie, and I really like the enclosure used. Thanks for posting this. Great video!

[@bobsbarnworkshop]

The switches have built in LED’s and current limiting, so just hook up the feed, load and neutral. I don’t remember where I bought them , probably eBay or amazon. I just searched for waterproof switches …. And the ones with the pilot lights came up. score! Thanks for watching!

[@sofiaoropesa]

can you make a step by step in how to build on a 8hp for diy?

[@bobsbarnworkshop]

I am actually at the lake for 4th of July week. Maybe I can open up the control box and show the details of how it goes together.

[@bobsbarnworkshop]

WOW! this is my most popular video! Most any brand outboard can be upgraded to electric start. The key here is the control box, nothing inside the motor itself other than the electric starter motor (and hopefully yours will already have the ring gear!) And no need for a huge expensive battery, my lawn tractor battery runs this rig all season without recharging. You probably can use 10gauge wire instead too. I didn't check the current draw so I just went large.

[@granio95]

Bob's Barn Workshop Bob, any way you have a part number or link to the 50A connector you used? I see similar products online but the one you’ve got looks bette quality that what my internet searches are bringing up. Thanks! And great video, very simplified way of doing it.

[@bobsbarnworkshop]

@@granio95 I got the Anderson SB50 connectors on a website called powerwerx.com here's a link to the page and connectors. I got all the connector waterproof covers here too. Make sure you get two terminals for each connector you use. I think I got the 50 CB, 20A fuse holder, 6 gauge wire here too. I think the 50A circuit was overkill, probably could use 8 or 10 gauge wire and reduce the main fuse to match the wire, 40A for #8 wire, 30A for #10. I included the link to the page below. Thanks for watching! powerwerx.com/anderson-power-powerpole-sb-connectors#/specFilters=129m!#-!307&pageSize=90&orderBy=0&pageNumber=1

[@smiithy85]

Hey mate I've got a 15m 1980s mariner as well where did you get the eclectic fly wheel from could you post all the products you used

[@bobsbarnworkshop]

See the pinned post on the video, all the parts are there. Thanks for watching

[@billgregory9560]

yes thanks Bob it was , im strugling with the conversion but becoming more informed thanks

[@bobsbarnworkshop]

See this post again, I found my paper with all the part numbers. Good luck!

[@timw8796]

I have A 96 Yamaha I wanna do this to its a 25hp will this work

[@bobsbarnworkshop]

You will need to make sure your outboard has a ring gear and mounts for a starter motor. Of course you will need to find the correct starter motor and ring gear if it’s not already in the motor . All of the electronics are in the external battery-control box. It’s just a relay and a push button. Good luck! Thanks for watching!

[@Chilipal]

I have a solenoid already mounted on the motor, it wAs originally all setup for remote but I’m using only tiller now. How can I set up the power box with button like you have? Do I still need a relay or do I have to run the starter wires along with the battery cables? The quick connect is awesome tho.

[@bobsbarnworkshop]

My motor didn't have a starter motor so I had to install one. There was no relay so I needed one in the battery box. If your starter has the relay (solenoid) already on it , you could just add the push button switch somewhere on the motor cowel or handle somewhere. Tap the power off the cable coming in from the battery box but install a fuse in line close to that connection, a big battery can supply huge power and melt down and burn up wires and your motor in seconds! Good Luck! Thanks for watching!

[@aaronochoa1597]

Can you put electric start on a 2.5 mercury?

[@bobsbarnworkshop]

if it has mounting points for the starter? gear on the flywheel? year? I have no idea, but good luck!

[@theanglerboy]

Great job! I have a 1988 Mariner 25 (Manual start) which is identical to yours and wondering if you would be interested in building the same system for me minus the ring gear and starter motor (I have those.) I'd like to have it all contained in the battery box with the quick disconnect. Let me know and thanks!

[@bobsbarnworkshop]

It’s really not hard to build! Some 6ga wire for the primary wires to the starter relay from battery positive ( I put in a self reset 50 A breaker in between) to an Anderson 50A 2pole connector, to the starter, ground back through the Anderson connector and to battery negative the rest is just small wire to the relay coil (through a fuse first) through a momentary push button to battery negative. That’s it! I suppose I could build you one.? Want any other accessory switches? I have navigation lights and bilge pump

[@theanglerboy]

@@bobsbarnworkshop I watched your video a few more times and I think I can do it. I'll keep you posted. Thanks for getting beck to me!

[@bobsbarnworkshop]

@@theanglerboy I made a home made terminal crimper for the big connectors by drilling a hole in a piece of hardwood the same diameter as the terminal barrel, then split it through the center of the drill hole. Then I stripped the wire , put it in the terminal, laid it in the half hole and used a screwdriver and a hammer to make a nice firm indent to make the connection tight! Good luck! Sorry I didn’t film the actual construction. I bought the 12v relay at autozone for about $14, I had the big plastic battery box around the lake forever!

[@nz2386]

Can you use any solenoid , flywheel , starter motor aslong they fit or do all the parts have to be for that exact model outboard?

[@bobsbarnworkshop]

The flywheel and starter would be specific to the make and model of motor, however they use the same parts on a family of models, for example on a 20 and 25 hp. Starter motors fit many models. The relay and electrical parts are not specific, anything that meets the requirements. Hope that helps Thanks for watching

[@nz2386]

@@bobsbarnworkshop thanks mate we need more magivers around like this only vid i could find, i have a 12ft dinghy and a tiller 9.9hp 1990 mariner engine going to convert to steering wheel throttle control and electric start any help be amazing

[@bobsbarnworkshop]

@@nz2386 look at the flywheel for a ring gear with starter teeth. If you have that you’re well on the way! Also you need to look for a mounting position for an electric starter, if that’s there then all you need are the parts. Internet search, ebay and Amazon are good sources but there are also dedicated Metcury/Mariner parts websites which are also very good sources. You will need the motor part number and serial number, found somewhere on the motor to find the correct fit of the starter motor. Starters are very universal and there are only a few different models so it should be easy to find. I also have a video of me adding a charging coil and rectifier to the same motor, check it out Good luck ! Thanks for watching!

[@billgregory9560]

is the ring gear just bolted to the existing flywheel is what I meant

[@bobsbarnworkshop]

I’ve been looking at eBay, Amazon and PayPal but I can’t find the ring gear purchase. I believe I got it from a Mercury parts dealer. Search there, I’m sure you’ll find it and a diagram showing the exact bolts too. Good luck!

[@billgregory9560]

@@bobsbarnworkshop thanks bob

[@bobsbarnworkshop]

@@billgregory9560 i THINK THIS IS THE CORRECT PART BUT LOOK UP YOUR SERIAL NUMBER ON THE MERCURY MARINE WEBSITE AND LOOK AT THE PARTS DIAGRAM TO CHECK. www.ebay.com/itm/174691241006?chn=ps&norover=1&mkevt=1&mkrid=711-117182-37290-0&mkcid=2&itemid=174691241006&targetid=1068323853270&device=c&mktype=pla&googleloc=9005452&poi=&campaignid=11758057844&mkgroupid=115806620084&rlsatarget=pla-1068323853270&abcId=9300462&merchantid=6296724&gclid=CjwKCAjwgZuDBhBTEiwAXNofRNlsWhjopD0Lpg6xjZlahdXHv2mZ6OYKuC0UKZPmzbiwtdtA4eTVORoCX6YQAvD_BwE

[@stacyzimmerman6212]

Great just what I e been needing to see. Can you or are you still replying to this video Bob?

[@bobsbarnworkshop]

Yes! I try to respond to every question!

[@bobsbarnworkshop]

One thing I noticed is that I actually connected the 20A fuse to the hot side of the 50 CB.. doesn't really effect anything either way you do it.

[@johncooper6246]

Well, from what I see you connected the 20A fuse to the load side of the 50A fuse. It only means that if anything on those parallel branches (bilge pump) were to dead short it could possibly blow both fuses. But if that happened wire jacket may start melting first. You would smell it, cheers.

[@noahhobbs449]

Bob where did you find the choke assembly I'm needing one but can't seem to find it I have the same motor

[@bobsbarnworkshop]

I wish I had documented everything I bought but I just don’t have a link to the part or where bought it, but there are several big mercury part suppliers on line I’ve used so I assume it was one of them. I’ll search my Amazon and ebay history and see if I can find it… sorry

[@bobsbarnworkshop]

see the post again, I pinned it to the comments

[@billgregory9560]

Hi again Bob getting back to the electric start conversion on your mercury, its the same motor as mine ,,tell me when you had to add the ring gear does it just bolt on to the underneath of the pull start mechanics,also do you have a part number for it thanks

[@bobsbarnworkshop]

To add the ring gear you’ll have to pull the flywheel with a puller. It may be possible if you pry under the edge and rap on the center bolt (leave the nut on loose to prevent damaging the threads of the shaft) but I used a puller, they’re cheap insurance! The ring gear bolts to the bottom of the flywheel with six small metric bolts, sorry I don’t remember the size of the bolts or the ring gear part number but if I think of it when I’m on my big pc, I’ll check for purchases, maybe I’ll get lucky and find it on ebay or Amazon.

[@bobsbarnworkshop]

Here's the ring gear I think... #99301 but go to the official Mercury Marine website with the serial number of you motor and look up the parts diagrams to find it, then search for that part number, this is the part number I found on ebay: www.ebay.com/itm/174691241006?chn=ps&norover=1&mkevt=1&mkrid=711-117182-37290-0&mkcid=2&itemid=174691241006&targetid=1068323853270&device=c&mktype=pla&googleloc=9005452&poi=&campaignid=11758057844&mkgroupid=115806620084&rlsatarget=pla-1068323853270&abcId=9300462&merchantid=6296724&gclid=CjwKCAjwgZuDBhBTEiwAXNofRNlsWhjopD0Lpg6xjZlahdXHv2mZ6OYKuC0UKZPmzbiwtdtA4eTVORoCX6YQAvD_BwE

[@bobsbarnworkshop]

see this post again, all info is pinned in the comments.

[@jacktregellas5962]

Where did you get the ring gear? I have a 25hp of similar year and can’t find anything.

[@bobsbarnworkshop]

the ring gear part number is: 43-99301, I just searched and found several sources including Amazon. It attaches to the flywheel with 4 metric bolts, M5X13 Funny coincidence is that I just came across the scrap paper I had the part numbers written on

[@cummins130]

Hey Bob, do you think this would be doable with a 1979 mercury 9.9

[@bobsbarnworkshop]

Seeing everything except the starter motor is external, I see no reason why not! You’ll need to check for or buy a ring gear ( or a used flywheel with one) and check if there’s mounting holes for the starter. Good luck, ket me know how it works out!

[@tegrof245]

Are you charging the battery Off of the motor?

[@bobsbarnworkshop]

Tegrof not back when I did this upgrade, but about a month ago I uploaded a video where I do add a charging coil and rectifier to this motor

[@johnnylemoine2478]

where did you get the Plug for the 6 gauge wire and what is it called ???? and where did you get the starter button at ??

[@bobsbarnworkshop]

From a website called powerwerx.com/anderson-sb-connectors-sb50-50amp

[@johnnylemoine2478]

@@bobsbarnworkshop Thank you BOB , I am getting all my Parts to Build Mine thanks man . working on a 1981 Johnson 25 HP . Putting a starter on it

[@bobsbarnworkshop]

Johnny Lemoine I think maybe 10 gauge wire would be large enough,? But better too big than too small. Let me know how your project turns out! Good luck!

[@sharmanprice2601]

I have a 1967 evenruge 20 h would love for some one to put a electrical starter on mine

[@bobsbarnworkshop]

Sharman Price first check for two things, if there are gear teeth on the flywheel and if there’s a mounting place for the starter motor. If it’s got both of those, the rest is easy!

[@Gdawon]

How difficult was it to track down a ring gear flywheel? Did you replace the whole flywheel or just add a ring gear?

[@bobsbarnworkshop]

I don't remember the exact place I bought the flywheel gear, but I had to pull the flywheel (I have a puller) and screw on the ring gear... I think it took 6 or 8 small metric bolts. so I reused the flywheel. I think I looked up my engine model on the parts list on a website and then searched for the part number on line. good luck!

[@bobsbarnworkshop]

Gdawon maybe you can find a compatible motor to salvage a flywheel with a ring gear on it?

[@bobsbarnworkshop]

Maybe the right part www.ebay.com/itm/174691241006?chn=ps&norover=1&mkevt=1&mkrid=711-117182-37290-0&mkcid=2&itemid=174691241006&targetid=1068323853270&device=c&mktype=pla&googleloc=9005452&poi=&campaignid=11758057844&mkgroupid=115806620084&rlsatarget=pla-1068323853270&abcId=9300462&merchantid=6296724&gclid=CjwKCAjwgZuDBhBTEiwAXNofRNlsWhjopD0Lpg6xjZlahdXHv2mZ6OYKuC0UKZPmzbiwtdtA4eTVORoCX6YQAvD_BwE

[@Gdawon]

@@bobsbarnworkshop thanks mate, not sure? Mercury part for a Yamaha outboard?

[@bobsbarnworkshop]

Part number of the ring gear: 43-99301 available several places including Amazon

[@billgregory9560]

to bad you didnt have a video on actually installing the flywheel stratos and starter motor and starter switch that would have been more helpfull rather than the carb info wire size ect ect

[@bobsbarnworkshop]

I made the electric start conversion before I started this channel, so unfortunately I didn’t start filming when I built the remote battery box and did the starter motor and the ring gear installation on the flywheel. There’s plenty of videos how to pull a flywheel on an outboard so that would be rather redundant. I think I mention the wire gauges and circuit explanation as well as I could after the fact... hope you got some useful info anyways. Thanks for watching!

[@bobsbarnworkshop]

Where I got the Anderson SB50, 50 amp connectors, wire, circuit breaker and fuse holder: powerwerx.com/anderson-power-powerpole-sb-connectors#/specFilters=129m!#-!307&pageSize=90&orderBy=0&pageNumber=1 11 minutes ago (edited)

[@bobsbarnworkshop]

$350 total for all the parts

[@vitoscatigno4207]

And what did he show us? NOTHING!!!

[@bobsbarnworkshop]

Did you watch the video and explanation of the circuit? Seems pretty clear to me, but I was in electronics for 35 years… sometimes things that seem obvious to me may not be to others! feel free to ask questions and I’ll do my best to give you a clear answer. The engine parts I bought are listed in my pinned comment. Thanks for watching!

[@sofiaoropesa]

i am not sure it is “extremely simple”

[@bobsbarnworkshop]

A battery through a relay and a pushbutton, pretty simple!

[@loydtromblay411]

What kinda of instruction video is that. Its done already

[@bobsbarnworkshop]

Yeah, I had to install the starter on the engine, pull the flywheel to install the ring gear, and build the battery box control unit. Sorry I didn’t film that, just wanted to get it done. I hope the description and schematic provided some useful tips, it’s not that complex but I’ve worked with circuits most of my life! If you need any more help let me know and I’ll do my best to provide any info I can! Thanks for watching!

[@bobsbarnworkshop]

I’m actually trying to locate parts to do the same kind of conversion on my lake neighbor’s 20hp yamaha outboard next summer!

[@josephsarsero7668]

I have a Mercury Marine outboard motor and I wont to fine the Right starter motor (SERIAL NUMBER ONO45091-- 2005-- ME30 EMLH 30HP CAN YOU PLEAS HELP ME

[@josephsarsero7668]

I have a Mercury Marine outboard motor and I wont to fine the Right starter motor (SERIAL NUMBER ONO45091-- 2005-- ME30 EMLH 30HP CAN YOU PLEAS HELP ME