2007 Mercury 115 efi (4-stroke) - not charging the battery

My 2007 Mercury 115 efi (1b484248) has stopped charging the battery. Spent 4 hours with AI today trying to diagnose this. Been trying to find the The Stator-to-Regulator Plug/Connector to check the voltage and have been unable to locate it on this motor. I can't even find the voltage regulator (which is the likely culprit). I watched multiple videos and my motor layout doesn't match any of them.

I have looked for yellow wires coming from underneath the flywheel - none there. Can anyone point me to the voltage regulator on this particular motor? I fear it is behind the manifold and it seems like a sizable job to remove it - especially with the boat in the water, which it is.

Pics of the motor are attached. Thanks for any help!

That thing with the belt driving it (top left of 1st pic ) is the alternator , and there is every chance that the rectifier and regulator are inside that ,so there will be no 3 yellow wires to see , more likely one biggish wire leaving the alt which will be the charging wire that possibly goes to a fuse ( I dont know your motor ,I just saying what you would normally find ) or maybe even the battery+ terminal on the starter solenoid . In the 2nd pic (bottom left in pic ) there is a fat red wire with a long off yellow heat shrink ( might be an in line fuse ) on it ....might be the alt output . Hope that helps

You seem to be looking for a permanent magnet alternator which is not used on your model. As noted in the post above, a conventional electromagnet alternator is used. See photo below.

The rectifier/regulator is a component within the alternator assembly.

Hopefully just the fuse in the fused harness is blown. See the bottom photo.

Mc Tool said:

That thing with the belt driving it (top left of 1st pic ) is the alternator , and there is every chance that the rectifier and regulator are inside that ,so there will be no 3 yellow wires to see , more likely one biggish wire leaving the alt which will be the charging wire that possibly goes to a fuse ( I dont know your motor ,I just saying what you would normally find ) or maybe even the battery+ terminal on the starter solenoid . In the 2nd pic (bottom left in pic ) there is a fat red wire with a long off yellow heat shrink ( might be an in line fuse ) on it ....might be the alt output . Hope that helps

Click to expand...

Thanks for the help. You mentioned the starter solenoid - how is that involved? A couple of weeks ago, I touched the started solenoid with a screwdriver and threw a spark - I was thinking maybe this caused the issue, but I wasn't sure how.

boscoe99 said:

You seem to be looking for a permanent magnet alternator which is not used on your model. As noted in the post above, a conventional electromagnet alternator is used. See photo below.

The rectifier/regulator is a component within the alternator assembly.

Hopefully just the fuse in the fused harness is blown. See the bottom photo.

Click to expand...

Thanks for the help! Since the voltage regulator is housed inside the alternator, how do I test it? If it is blown, do I need replace the alternator or is it componentized? i.e. can I possibly replace just the VR component?

Gee, what do the parts diagram at a place like crowleymarine list for replaceable components? In the 80's one could get parts for automotive alternators. like brushes and diode bodies. Not sure what is avail now.

justice802 said:

Thanks for the help! Since the voltage regulator is housed inside the alternator, how do I test it? If it is blown, do I need replace the alternator or is it componentized? i.e. can I possibly replace just the VR component?

Click to expand...

You test for output directly at the alternator. With the alternator being connected to a known good battery after having confirmed that the wiring to the battery is in good condition. If there is no or substandard output the modus operandi today is to replace the alternator as one unit. Using an OEM or aftermarket alternator. Or you can take it to an alternator rebuild shop and let them fix it for you. They will know which internal component(s) need to be replaced.

You might do a google search to see if anyone has come up with part numbers for the alternator internal parts. Diodes, regulator, stator, rotor, bearings and such. You won't be getting this from Mercury Marine I suspect.

Chris1956 said:

Gee, what do the parts diagram at a place like crowleymarine list for replaceable components? In the 80's one could get parts for automotive alternators. like brushes and diode bodies. Not sure what is avail now.

Click to expand...

Given the high costs of labour here in the US, the days of repairing components such as an alternator seem to be long gone. Do marine mechanics even know how to do this today? Easier, faster and more than likely cheaper just to throw a new alternator own. With better assurances that a problem will be fixed.

Interesting to me that Mercury Marine once used a separate electromagnet alternator on some 115 models and now seems to have changed to the permanent magnet type of alternator.

I get most of my rotating electrics rebuilt vs replacing. I used to drive past a starter/alternator shop every day prior to changing jobs. still use them, just a little less convenient.

they give you a test report.