2008 Yamaha F40 install the optional rectifier/regulator

outfishing13

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I recently purchased a 2008 Yamaha F40. This is the manual start with a tiller arm. I read in the owner's manual that an optional rectifier/regulator can be installed so one can charge a battery for electronics, lights and electric trolling motor. So I purchased a kit and got it in the mail the other day.

Well, searching the web had been fruitless and I have not found any instructions how to hook up the thing.

The rectifier/regulator kit has 5 wires. Two idential (green/whites) with single male ends. One (black) ground. And a long bundled pair (one red, one black) to go to the battery, the red having an inline fuse.

When I look at the engine there are two yellow female lines that have the same corresponding plugs that would match the rectifier/regulator. I am thinking that is what I plug it into since those go right to the lighting coil.

On schematic in the service manual, there isn't a corresponding green/whites to hook up the rectifier/regulator to the stator(lighting coil). However, when I look at the manual for the charging system, page 8-28, it shows that two yellow lines(just like on my engine) hook into the regulator/rectifier.

My question is, is the two yellows the correct lines to plug into the green/whites on my regulator? I am just thinking that this is a newer rectifier/regulator and the wire colors don't match, but those are the right ones to hook up.

Help would be greatly appreciated.

By the way. I love the motor! My first 4 stroke. I can troll for 3 hours, zoom around some and burn a little more than a gallon of gas.

Thanks,
Matthew
 

boscoe99

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Re: 2008 Yamaha F40 install the optional rectifier/regulator

There are F40's and there are F40's. You need to provide the complete model of the motor that you have. It is more than just F40.
 

outfishing13

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Re: 2008 Yamaha F40 install the optional rectifier/regulator

I am pretty sure it is a model F40 MLH. I will double check when I get home this evening.
 

boscoe99

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Re: 2008 Yamaha F40 install the optional rectifier/regulator

How about an F40BMLH?
 

boscoe99

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Re: 2008 Yamaha F40 install the optional rectifier/regulator

What is the kit number?

Why did you not buy the F40 regulator rectifier that fits an F40BTLR?
 

outfishing13

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Re: 2008 Yamaha F40 install the optional rectifier/regulator

when I say "Kit" I just got what the Yamaha dealership recommended. He sold me the required nuts and bolts and mounting bracket and the rectifier/regulator that works on the model number I gave him.
 

boscoe99

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Re: 2008 Yamaha F40 install the optional rectifier/regulator

Reason why I ask is because an F40 R/R has five wires coming from it. Two yellow (connect to the two yellow from the lighting coil), a black going to a ground on the block, a red going to the battery and a green for the tachometer signal.

Not sure what R/R you have. I would guess that the green/white bullet connectors go to the yellow female lighting coil leads, one black to a block ground, the other black to a battery negative post, the red to a battery positive post.

Does the motor start, idle and accelerate well? Hope so. The carb'd F40 can be a bit problematic. Keep those carburetors clean.
 

outfishing13

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Re: 2008 Yamaha F40 install the optional rectifier/regulator

Thanks for the information. Yes, the motor runs and starts very well. What is the best way to keep the carbs clean?
 

boscoe99

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Re: 2008 Yamaha F40 install the optional rectifier/regulator

Try this. The two ground ring terminals go to a bolt on the engine block. Don't over tighten that bolt after installing the ground terminals.

 
Last edited:

boscoe99

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Re: 2008 Yamaha F40 install the optional rectifier/regulator

Thanks for the information. Yes, the motor runs and starts very well. What is the best way to keep the carbs clean?

If you have had the motor since new with no problems then just keep doing what you have been doing. If it ain't broke, it does not need to be fixed.
 

99yam40

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Re: 2008 Yamaha F40 install the optional rectifier/regulator

Thanks for the information. Yes, the motor runs and starts very well. What is the best way to keep the carbs clean?

a 10 micron water separator/ filter inline before it gets to the motor is one good way.
And keeping good fresh fuel in the tank and run often
 

outfishing13

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Re: 2008 Yamaha F40 install the optional rectifier/regulator

Thanks for all the tips and information. After the tips and such and carefully looking over the situation, I am confident I can get everything hooked up correctly this afternoon. I'll hook up the motor to a hose and test things with a meter to make sure I am charging. I am really looking forward to getting my new fish finder up and running and eventually I will have some nice downriggers to go troll for kokanees.

Thank you, iboats, for the forum and all the great people out there in the boating community!

Matthew
 

outfishing13

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Re: 2008 Yamaha F40 install the optional rectifier/regulator

Well, I got the R/R installed and it works just fine. Thank Boscoe99 for posting that diagram. That is exactly what I needed to complete my install. Very happy with getting that done.

As I mentioned before, the engine seems to start and run very well, however, it seems to shake a lot while trolling at a slow idle and has a little problem getting up to power. Since I am pretty new to 4-strokes I am not sure it really should operate like that, so I think I will start a new thread.
 

99yam40

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Re: 2008 Yamaha F40 install the optional rectifier/regulator

I have read the F40 is a motor that has very small jets/passages, and is a very difficult motor to adjust the carbs properly on
 

boscoe99

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Re: 2008 Yamaha F40 install the optional rectifier/regulator

I have read the F40 is a motor that has very small jets/passages, and is a very difficult motor to adjust the carbs properly on

It started life with small jets. Then, in 2003 they reduced the size of the pilot jet from a #40 to a #38. More than likely to meet EPA requirements.

Many that have had problems have removed the #38 and gone back to the #40, or even stepped up a few other sizes. The main jet can also be increased in size if there is a problem at high speeds.

A motor that is about to be dismantled for parts (because of the frustration with it) can be made to run better than new, just by changing jet sizes.
 
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