two big problems

[wenied]

I have a 2003 mercury 25 hp two stroke. It's sat for 2 months and not wont run. We'll worry about that part later...i think the carb just needs a clean out...

Here is the problem..i removed the battery because it was weak...i wanted to charge it. When i placed my spare battery in the boat and attached it a fire occurred.
As soon as i attached the battery the component shown in the photos started burning and shooting sparks out of it. What is this component and what could cause this.
I'm talking about the box below the switch box with 2 yellow one black and one red wire coming out of it.
(yes i hooked the battery up right and yes the key was off)

Thanks,
David Wene
Mechanical Engineer

 

[tsgarbi]

Re: two big problems

I have a 2003 mercury 25 hp two stroke. It's sat for 2 months and not wont run. We'll worry about that part later...i think the carb just needs a clean out...

Here is the problem..i removed the battery because it was weak...i wanted to charge it. When i placed my spare battery in the boat and attached it a fire occurred.
As soon as i attached the battery the component shown

in the photos started burning and shooting sparks out of it. What is this component and what could cause this.
I'm talking about the box below the switch box with 2 yellow one black and one red wire coming out of it.
(yes i hooked the battery up right and yes the key was off)

Thanks,
David Wene
Mechanical Engineer

David,
It looks like the voltage regulator.
How old is your spare battery? before you re-connect make sure it is not a defective battery delivering more than 12V

 

[JUSTINTIME]

Re: two big problems

yep rectifer
2 yellows are a/c in and red is 12v dc out

 

[wenied]

Re: two big problems

Thank you both for the reply! I was using this battery earlier today without issue...it's about 6 months old. It has 12.3 volts right now.

Would a faulty rectifier keep the motor from running?

 

[JUSTINTIME]

Re: two big problems

no, it just charges your battery
u need to find out why it sparked
look for blown fuses and grounded out wires, corroded wires

 

[wenied]

Re: two big problems

no, it just charges your battery
u need to find out why it sparked
look for blown fuses and grounded out wires, corroded wires

Ugh!! I just checked and i do not see any corroded or uninsulated wires.
So basically the stator creates the power and the rectifier converts it to DC and sends it to the battery?
This leads me to believe that a problem within the rectifier could draw power away from the spark plugs...
Maybe i'm overthinking this.... I guess i could go to radio shack and buy a 3 dollar rectifier instead of paying mercury for one....

I may just be hoping this caused the motor not to run. for the past few days i could not get the motor to start at all with the starter...(it would spin the motor but the motor would never start)...a few times i disconnected the battery and on the first pull of the pull rope the motor starts.....done this 3 times now....but it dies about 15 seconds later.....I'm stumped.

 

[JUSTINTIME]

Re: two big problems

check
spark
compression

go from there

 

[wenied]

Re: two big problems

Spark and compression are fine from what i can tell...
the plugs are wet with fuel each time i pull them..

check
spark
compression

go from there

 

[Plainsman]

Re: two big problems

But are you getting spark?

 

[wenied]

Re: two big problems

Before the aforementioned fire from above i tested the spark by doing this:
I pulled the plugs...held them by the wire...and touched them to the engine block...wife cranked the motor....the plugs had a blue spark going from the plugs to the block.

But are you getting spark?

 

[Deimus]

Re: two big problems

But what about now? Get the wife or a neighbor out there and check spark again.

Once you let the factory installed smoke out of a wire it is very hard to put it back!dlol

 

[wenied]

Re: two big problems

But what about now? Get the wife or a neighbor out there and check spark again.

Once you let the factory installed smoke out of a wire it is very hard to put it back!dlol

LOL.
I haven't tested for spark since the fire. I'm assuming i should take off the rectifier before i try it.
The motor should be able to run without a rectifier right?

 

[ricksrster]

Re: two big problems

did you have the battery cables hooked up right? Red on pos and black on neg?

 

[wenied]

Re: two big problems

did you have the battery cables hooked up right? Red on pos and black on neg?

I did.....i double checked after wards to make sure.

 

[JUSTINTIME]

Re: two big problems

yes it will run with out it

 

[wenied]

Re: two big problems

Ok guys..here's an update..
I cut off the dead rectifier...cleaned the carb...dumped my fuel and got fresh fuel..added the oil and some sta-bil....cleaned the fuel filter.....then pulled the rope.
Motor started on the first pull.. I let it run for 20 minutes or so.

I then hooked up the battery....cranked the motor...it would not start(turns the motor fine..just wont fire).. I pulled the rope..it still will not start...

I disconnected the battery and it starts on the first pull.

So now the motor runs fine but will only start if the battery is disconnected....i tried both of my batteries..they both have a full charge....

HELP!!!

 

[akwalker]

Re: two big problems

Maybe a problem with your keyswitch or the harness back to the keyswitch that allowed battery voltage to get to the output side of your rectifier. I say this because when you connect the battery, you bring the starter switch into the picture, and you are losing your spark.

 

[wenied]

Re: two big problems

One more thing to mention is that i removed the rectifier and the same problem exists

 

[phatmanmike]

Re: two big problems

first off, get a new voltage regulator.

the CDI/RAPAIR aftermarket part is far better tha OEM. just a thought.

with the voltage regulator not hooked up, where does all that voltage that the stator is making, where does it go. your risking frying the stator.

 

[wenied]

Re: two big problems

first off, get a new voltage regulator.

the CDI/RAPAIR aftermarket part is far better tha OEM. just a thought.

with the voltage regulator not hooked up, where does all that voltage that the stator is making, where does it go. your risking frying the stator.

I bought a couple at radio shack for 3.29. I'll hook it up soon...the main point is the darn motor wont run with the battery hooked up..rectifier or not