Mercury not charging

[RUNWME]

Working on a friends engine because it isn't charging. I ordered a manual for this, but it wont be in until next week.

Here is the problem.

With key and fuel pump on ...engine off, have 12.45 volts (fresh battery)

Start engine and voltage drops down to 12.39 and the higher I rev the engine, the lower the volatage goes (12.21 at 5k rpms)

Tachometer is working fine....

What could be the problem? Voltage reg? Stator? Is there OHM resistance readings I should check for?

Thank you

David

[stvhelm]

what model engine? most likely its the rectifrier.

[heath brinkley]

I'll second the rectifier.

[RUNWME]

Thanx guys.. new rectifier helped,charging, but very low output.

Here is what is happening now.

Key off fuel pump off 12.61 volts(fresh charge on battery

Key on fuel pump on engine off 12.40 volts (engine not running)

Start engine and idle 12.41 volts

Rev to 3k RPMS 12.46 volts

I hooked up the voltage regulator(was disconnected) and if anything had less voltage :(

Engine is EFI. Holley EFI 100psi fuel pump.



I have switched stator, and flywheel with no change. I am running a light weight flywheel, but not sure how many amps the stator is... can you tell from this picture?


I am baffled....

[Simon]

That is a 16 amp stator, the fuel pump uses about 10-14 amps, the EFI uses a few also. Here is the answer. 50 amp alternator kit. It bolts right on and you leave the stator there. The total amps are 65 at 4500 rpm. They work great. More info at www.simonmotorsports.com

[RUNWME]

Eric, that simonmotorsports alternator is one HOT piece.
It would be cost prohibitive on this setup because he would have to buy not only the kit at 695 but also an alien cowl for another 500 or so to make it work. Would be a nice addition on my boat though :)

Will a mercury 40 amp stator work with a lightweight flywheel? Don't need alot more charging, just enough where there isnt a constant drain on battery while running.

Thanx

[WATERWINGS]

David, what does the metal plate part of the stator measure?

From what I understand, the 40 amp stator is a totally different creacher, (sp) and has to have all the other parts to go along with it to make it work??
(posably even a diffrent flywheel)

You better get that greasy mess off of the couch before Jenn grabs you by the throat for putting it on there in the first place!!
:D