Mercury Outboard Alternator

If your outboard motor is like most, it has an alternator that provides electricity to charge the battery and power the accessories. The average outboard motor has a 12-volt alternator, but some have a 24-volt system. If you’re not sure which voltage your outboard has, check the owner’s manual or ask your dealer.

When something goes wrong with the alternator, it can cause problems with starting or charging the battery. In this article, we’ll show you how to troubleshoot a mercury outboard alternator and get it working again.

If you have a Mercury outboard engine, you may be wondering if you need an alternator. The answer is yes! Mercury outboard engines are designed to run on 12-volt systems, and an alternator is needed to keep the battery charged.

Alternators are available from Mercury dealers or aftermarket suppliers.

Mercury Outboard Alternator


What are the Most Common Problems With Mercury Outboard Alternators

If you have a mercury outboard engine, chances are good that you will eventually need to replace the alternator. Alternators are what charge the battery on your boat, and over time they can wear out. Mercury makes both original equipment replacement alternators and aftermarket alternators for their outboard engines.

There are several things that can go wrong with an alternator, but the most common problem is simply that it wears out from use. The bearings in an alternator can wear down over time, causing the alternator to seize up and fail. This is especially likely to happen if you don’t regularly maintain your boat and change the oil in the engine.

Another common problem with mercury outboard alternators is corrosion. If your boat spends a lot of time in salt water, the salty air can corrode the internals of the alternator, causing it to fail prematurely. Corrosion can also be caused by moisture getting into theAlternator through cracks or other openings.

If you suspect that your mercury outboard’s Alternator is failing, it’s important to take it to a qualified marine mechanic or Mercury dealer for diagnosis and repair. Replacing an Alternator is not a difficult job, but it’s one best left to experienced professionals.

How Do I Troubleshoot a Mercury Outboard Alternator

If you are having trouble with your mercury outboard alternator, there are a few things you can do to troubleshoot the issue. First, check theAlternator Belt for proper tension. The belt should be tight enough so that it does not slip, but not so tight that it is difficult to turn the engine over.

If the belt is too loose, it can cause the alternator to not charge properly. Next, check all of the connections to ensure they are secure and free of corrosion. Finally, test the Alternator itself by using a multimeter to check for proper output voltage.

If you still cannot resolve the issue, take your boat to a qualified marine mechanic for further diagnosis and repair.

How Do I Replace a Mercury Outboard Alternator

If you have a Mercury outboard engine, chances are you will eventually need to replace the alternator. Alternators are responsible for charging the boat’s batteries while the engine is running. Over time, they can wear out and stop working properly.

When this happens, it’s important to know how to replace them so you can keep your boat running smoothly. To replace the alternator on your Mercury outboard engine, you will need: – A new alternator (obviously!)

– A set of wrenches or sockets that fit the bolts on your particular engine – A ratchet or impact wrench (optional but helpful) – Wire cutters/strippers (optional but helpful)

First, locate the alternator on your engine. It will be mounted near the front of the engine, usually on top of one of the cylinder heads. On most engines, there will be two wires coming from the back of the alternator – a thick red wire and a thin black wire.

These are the positive and negative leads from the battery respectively. Next, use your wrench or socket to loosen and remove all of the bolts that hold the old alternator in place. Carefully pull it off of its mount and set it aside – being careful not to drop it as they can be quite fragile!

Now it’s time to install the new alternator. First, check that all ofthe mounting holes line up with those on your new unit – if not, simply reorient it until they do line up before proceeding any further. Next, take each bolt in turn and start threading it into place by hand – this will help prevent stripping any threads when you go to tighten them down later.

Once all bolts are in place by hand, begin tightening them down using your wrench or socket until they are snug but not overly tight – remember that these units vibrate quite a bit so you don’t want them too loose either!

Fixing a mercury outboard charging system


If your outboard engine is more than a few years old, it’s likely that the alternator is not charging the batteries as efficiently as it could be. Upgrading to a newer, more efficient alternator can make a big difference in how long your batteries will last and how much power you have available.

Related: Outboard Alternator Kit

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