Motor just died

[rodbolt17]

earthed is whut dem furriners calls grounded .
kinda like a bonnet or candles.

[rodbolt17]

is this F40 carbed or fuel injected?
I cannot remember when the FI model came out.

[Eastbayboy]

I continued going through the electrical and found the Regulator Rectifier to have only 1.5 VDC (red wire) output. It should be 13VDC per the manual. The input voltage and resistance from the stator was good. I also went through the regulator rectifier wiring and found several of the reading OPEN when they should have 1.5V. There is also a gray wire coming out of the regulator that goes into the boat that I have no idea what it does.

Looks like a bad unit, but my question is could a bad rectifier regulator prevent the motor from starting, especially if the battery is good and charged??


Eastbayboy

[pstephens46]

I and others would suggest answering Rodbolt's question. He is the resident master tech.

[Eastbayboy]

99yam40, I did not do that. What I did was disconnect the CDI cable and 1) Turn key to OFF and measured resisance at the CDI kill switch pin (17), it was grounded, 2) turn the to ON and have the kill switch lanyard installed and pin 17 was open 3) Key ON remove lanyard, pin 17 was grounded.

Robolt17: My motor has a carb

Eastbayboy

[boscoe99]

"I have a 2008 F40BTLR 40HP, 4 stroke outboard."

All F40BTLR's have carburetors.

First F40 fuel injected models were the F40LA and F40LEHA.

[boscoe99]

The Rectifier/Regulator has nothing whatsoever to do with the motor starting and/or running.

[boscoe99]

earthed is whut dem furriners calls grounded .
kinda like a bonnet or candles.

Or a torch when they mean a flashlight. Even though it normally does not flash.

[rodbolt17]

I would check the inputs to the cdi and the output from the cdi.

[Eastbayboy]

I rigged up a cable to check the CDI output to the coils. I read about 38VDC unloaded on the coils and about 1VDC loaded. The reading should be 120VDC loaded.

Still think my CDI is bad and I'm running out of things to check.

B.O.A.T.

Eastbayboy

[ausnoelm]

Out on the water? How is this possible?

Some people have to work at being an idiot, to others it just comes natural......

[ausnoelm]

earthed is whut dem furriners calls grounded .
kinda like a bonnet or candles.

I wonder how it gets "grounded" in a boat? Must have a wire going to the bottom? (Well according to some) the engine is negative earth, meaning the negative battery supply is earthed/grounded/connected to the motor....

[panasonic]

I rigged up a cable to check the CDI output to the coils. I read about 38VDC unloaded on the coils and about 1VDC loaded. The reading should be 120VDC loaded.

Still think my CDI is bad and I'm running out of things to check.

B.O.A.T.

Eastbayboy

Do you know anyone with the same engine as yours and bum their CDI to try on your engine. Just two be absolutely sure the CDI is bad?

[rodbolt17]

the out put is bad.
how is the INPUT to the CDI.
that F40B is a merc motor painted Yamaha gray with the dreaded red stator.

[99yam40]

I rigged up a cable to check the CDI output to the coils. I read about 38VDC unloaded on the coils and about 1VDC loaded. The reading should be 120VDC loaded.

Still think my CDI is bad and I'm running out of things to check.

B.O.A.T.

Eastbayboy

If you are not using the correct voltage measuring device you will not be able to compare to the peak readings given in the manual.
But as Rod said if you use what you have to measure both inputs and out puts it may give you an idea what is going on.

good into but bad out is different from bad in and out