2009 Mercury 20Hp adding alternator

[Revelation]

I am looking at buying a 2009 Mercury Fish Camp Motor. The seller does not do modifications. I would like to add an alternator to a tiller handled manual start motor. It is an option on a new motor. I want to know if it is something I can add on myself by buying it aftermarket. The motor is a great deal for the hp, but I would like the convenience of charging my river boat as I fish.

 

[steelespike]

Re: 2009 Mercury 20Hp adding alternator

I think it is costly and will probably require a different stator.
The alternator is rated at 11 amps at speed much less as rpms go down.
Enough to maintain the battery but won't do much if your running a live well
and electronic equipment unless you run at speed a lot, and like spitting in the ocean for a trolling motor battery regardless of the speed.

 

[Expidia]

Re: 2009 Mercury 20Hp adding alternator

I looked into that after I bought a 2005 9.9 Merc. I paid like $1500 and they wanted another $1000 to add electric start and an alternator after market. You have to buy another fly wheel which has the alternator underneath it.

Pretty cost prohibitive in my opinion.

Same for electric start:

http://www.ausfish.com.au/vforum/showthread.php?t=121228

 

[TOHATSU GURU]

Re: 2009 Mercury 20Hp adding alternator

Is it a 2 or 4-stroke? If it is the 4-stroke model then you would need the rectifier at the link below:

http://www.internetoutboards.com/partdetail.asp?id=922

 

[Revelation]

Re: 2009 Mercury 20Hp adding alternator

It is 4 stroke.

Is it a 2 or 4-stroke? If it is the 4-stroke model then you would need the rectifier at the link below:

http://www.internetoutboards.com/partdetail.asp?id=922

 

[Revelation]

Re: 2009 Mercury 20Hp adding alternator

The parts that have been listed so far don't seem to be too expensive. It seems like the majority of the expense may be tied up in labor. I am reasonably technically inclined and am wondering if it can be done by a shady tree mechanic like myself without having to spend too much money on tools I will never use again?

I am conerned about the whole project not being worth it if I am not getting the power to keep battery charged for everything running. I will only be running a 44lb thrust troller, few led lights, and a cooler with a 12v air pump. Afterall, I have used troller on transom as main drive for 1/2 day trips on slow moving river before battery died.

 

[TOHATSU GURU]

Re: 2009 Mercury 20Hp adding alternator

All you need is the rectifier. Its mounted with two bolts and has plug and play wiring. Its so easy even a cave man could do it....Unless he was French.

 

[achris]

Re: 2009 Mercury 20Hp adding alternator

All you need is the retifier. Its mount with two bols and has plug and play wiring. Its so easy even a cave man could do it....Unless he was French.

And you don't need to use Merc genuine (About $50). Go to your local friendly electronics shop (Tandy, ect) and ask for a '40 amp bridge rectifier', cost about $5. They have 4 terminals, '+', '-', and 2 marked '~'. Hook the 2 yellow wires from under the flywheel to the 2 terminals marked '~', hook a black wire to the '-' terminal and connect that to the engine block, and finally get a nice pair of battery leads and connect the black to the block and the red to the terminal marked...... '+'. Job done..... Have a beer... (or three)....

Chris........

 

[TOHATSU GURU]

Re: 2009 Mercury 20Hp adding alternator

Just keep in mind that the use of a non OEM rectifier will void the warranty of the engine. On a new engine that would be a very foolish thing to do.

 

[Revelation]

Re: 2009 Mercury 20Hp adding alternator

Thank you for the information. I will try it out. As always, this forum has been the best source of information for my project. Thanks, again. Enjoy the water!