Yamaha F20BMH 2013 electrical

[merc200dalarna]

Hi, trying out this forum to see if I can get some advice.

My motor in topic was sold without electric start and charging coil.

I want to retrofit 12volt 10amp (or lower) charging for my fishfinder battery.

I have only very basic electrical knowledge, but am eager to learn, and it is not rocket science.

Can I find a lead wire on my motor to fit to a rectifier/voltage regulator? And then fit a charging output from the "other end" of the rectifier to my battery?

What parts do I need? Do I need a flywheel/stator upgrade aswell?

Swedish fisherman

[boscoe99]

The F20BMH model is not offered here in the US. We need the complete serial number please in order to try and find the USA equivalent. Then maybe we can offer you some good advice.

What are you doing up so late? Or early?

[merc200dalarna]

The F20BMH model is not offered here in the US. We need the complete serial number please in order to try and find the USA equivalent. Then maybe we can offer you some good advice.

What are you doing up so late? Or early?

Well, the full name is "F20BMHL", your models are probably "A" instead of "B". I know "B" stands for "inshore", probably similar to brackish water rating. And "A" is rating for full on saltwater. (My guess)
"MHL" is, as I guess you know, manual start, tiller handle and long shaft..

And off nada-guides for yamaha 2013 I think your model is called "F20LMHA" that is equivalent to mine.

I'm up early as it was a holiday here friday, and I fell asleep at 4p.m. =)

(Can't look for the serial as it is winter stored at boat storage)

[boscoe99]

A USA model F20LMHA is shown as having a lighting coil installed. If I were you I would put a voltmeter set to AC on the two lighting coil leads and confirm that you have voltage when the motor is running. Be careful and don't let your tie get snagged by the rotating flywheel.

The parts book for the F20LMHA shows alternate parts (AP) that appear to be available so that a regulated electrical output can be derived from the motor. See below.

[merc200dalarna]

A USA model F20LMHA is shown as having a lighting coil installed. If I were you I would put a voltmeter set to AC on the two lighting coil leads and confirm that you have voltage when the motor is running. Be careful and don't let your tie get snagged by the rotating flywheel.

The parts book for the F20LMHA shows alternate parts (AP) that appear to be available so that a regulated electrical output can be derived from the motor. See below.
(removed images for space)

OK, that advice on "alternative parts" was awesome. So without looking on my motor, I'm pretty sure I have a coil for the ignition and perhaps one for onboard lighting. Yamaha might even have the ignition/lighting as their base coil, and the alternative part is one with enough output for charging. I will lift off the rope start assy when I get the chance and look for the part number "4". Many thanks mister Boscoe

[boscoe99]

Your model should have four coils. Three of which are in use doing other jobs.

The lighting coil will not be connected. The lighting coil will be connected to the AP rectifier/regulator so that a battery can be charged.

[merc200dalarna]

Your model should have four coils. Three of which are in use doing other jobs.

The lighting coil will not be connected. The lighting coil will be connected to the AP rectifier/regulator so that a battery can be charged.

But what does my "charging coil" do? Because that is the one I want, I believe, to charge my battery? The pulser and auto-choke coils are used on mine...
Edit# Let's hope you are right. Because I can't see where my charge coil should be used since I can't charge anything.
Instead the charge coil should be the one I should regulate via rectifier to DC, or?

[boscoe99]

In a Yamaha the charge coil charges a capacitor in the CDI box. The pulser coil tells the CDI when to deliver the charge stored in the capacitor to the ignition coil.

Think of the lighting coil as producing some electrical power to light up some lights. Electrical power is provided to the battery and the battery provides it to the lights.

[merc200dalarna]

In a Yamaha the charge coil charges a capacitor in the CDI box. The pulser coil tells the CDI when to deliver the charge stored in the capacitor to the ignition coil.

Think of the lighting coil as producing some electrical power to light up some lights. Electrical power is provided to the battery and the battery provides it to the lights.

Ok, thanks. Off an australian site I saw that the lighting coil produces 120watts. No idea what that means though. I compared rotor/stator off boats.net and both manual and electric has same parts numbered listed (but also alternative parts for both, made me unsure) If I understand you right it is the lighting coil that is infact used to charge onboard batteries with 12volt 10amp? Just by looking at the numbers makes me suspect it to be true, since 10x12 equals "120", and if it happens to be one of those formulas I read about in school about electricity on how to find the "3rd" when one and two is given.
To sum it up: I need to find the unused coil and see what AC output it has, if it has proper output (what, I don't know) the parts I need is the rectifier and its wiring harness with a fuse? From what I see I do not get an "outlet" (like a wall socket..) but 2 pins for the battery! I had a honda once and it had an outlet on the motor...
Well, anyway I think I have the "theoretic" side covered now, will probably be as dumbfunded when I finally stands before my rotor...
I very much appreciate your time Boscoe.
Thank you very much.

[merc200dalarna]

Could it be that easy? The red arrow shows where 2 green wires come from the stator. Into that "plinth" (dunno what you call that piece of plastic where the wires comes together) but both outlets are plugged on the other end (2nd pic) would be awfully conveniant if that is where I should find AC current?

[rodbolt17]

those two green wires are indeed for battery charging OR A/C lighting.
if you want DC then you have to add a rectifier kit to your engine.

google OHM'S law.

you will find the info on converting watts to amps.

remember the lighting coil produces a VARYING a/c voltage.

[boscoe99]

It is that easy. Just follow the instructions.

The parts catalog for your model shows the two lighting coil leads as having a plug in each of them. Since they are not normally used on a manual start tiller handle model F20. That is what the MHA is about in the parts book. M = manual. H = Handle as in tiller handle. A = the model variant.

The plugs are removed and the rectifier/regulator leads plug into the lighting coil leads. See below:

[merc200dalarna]

It is that easy. Just follow the instructions.

The parts catalog for your model shows the two lighting coil leads as having a plug in each of them. Since they are not normally used on a manual start tiller handle model F20. That is what the MHA is about in the parts book. M = manual. H = Handle as in tiller handle. A = the model variant.

The plugs are removed and the rectifier/regulator leads plug into the lighting coil leads. See below:

Now that sounds simple enough for me. I sure appreciate both of your input.
So when I buy the rectifier assy, I will use the 2 wires with a male connector
where my plugs are? The rectifier assy has 5 wires, I believe, and the ground is the black wire with a circular "connector"? It leaves me with 2 wires, and I want to put the fuse on the positive lead going to the battery? What sort of battery-wire (name, specs etc.) should I use for the 2 leads to the battery?
Can I tell somehow what wire is "plus" or "minus"?

Well, I think I have the theory of it all nailed, still to be seen if I can make it work. Gotta say I love the internet for help like this. Thank you!

[rodbolt17]

one lead from the engine block (a ground) to the batt -.
the other fused from the red regulator lead to the batt +.
you could use a marine grade two wire romex and heat shrink crimp connectors in about a 10Ga wire.
10 ga is overkill but it wont be as susectible to chafing.
at or near wot you may see 8-10 amps DC.

[99yam40]

Just to make it clear to merc, you will not get very much amperage out at low RPM.
120 watts, 10 amps may be seen only at WOT