1996 Mariner 150HP Overcharging Batt 16.5Volts

[thewatercallsme]

Curently my 150HP Mariner (2.5L) is pushing the battery to over 16volts. The battery in nearly new and has plenty of water in it. The boat only has one battery in it with no battery switch, direct wired to engine harness. I'm assuming the voltage regulator on the alternator is fried. I've only noticed this the last time I went out b/c my GPSMapper gave a warning that it was shutting down b/c of to much voltage. Help please, supposed to fish it tommorow

 

[Laddies]

Re: 1996 Mariner 150HP Overcharging Batt 16.5Volts

A loose or dirty connection or a bad voltage regulator

 

[thewatercallsme]

Re: 1996 Mariner 150HP Overcharging Batt 16.5Volts

Bob, Thanks for the quick response. <br /><br />The battery terminals are as clean as can be but I'm unsure of the connections to the alternator. Should I be concerned with the connections at the alternator's end, the cowling has never had any water in it, but I do use the boat in the saltwater. <br /><br />Where is the alternator anyways, under the flywheel or near the starter. Also, if the reg/rec are bad are they integral to the alternator or seperate devices. <br /><br />I've got a decent level of mechanical skills and am trying to avoid the shop if possible, point me in the proper troubleshooting direction. -THX

 

[kchunn]

Re: 1996 Mariner 150HP Overcharging Batt 16.5Volts

I've got a 175 Mariner, and I just experienced the same problem you're having. In my case, it was the voltage regulator going bad. Some of these engines have 16 amp charging systems, and some have 40 amp charging systems. The 16 amp has the voltage regulator located directly behind the flywheel. Small square shaped part with a red and yellow lead. It's about $140. On the 40 amp system, however, the voltage regulator/rectifier is located behind the plate that is located in between the coils. If you see any wires coming from under that plate, you probably have the 40 amp system. If not, it's the 16 amp. If it's the 40 amp system, it's expensive. That voltage regulator/rectifier is about $440. I replaced mine myself since I had the 16 amp system, but if you have the 40 amp system, you might want to let a Merc tech at least diagnos it for you. Probably don't want to run it anymore until it's fixed. It could start damaging other electrical parts. (Stator, etc.)<br /> Good luck,<br /> Kenny

 

[thewatercallsme]

Re: 1996 Mariner 150HP Overcharging Batt 16.5Volts

Thanks Sabre175,<br /><br />I took the hood of tonight and I think I have the 40AMP Alternator. There is a module behind the plate that holds the two coils that has 6 red and 6 yellow wires coming out of it. Actually, I think there are two modules that have 3 wires of each color. The module seems about the size of a pack of cigaretes and has silicone over the computer chips. Is this the possibly bad module or is it related to something else? The yellow wires go to the windings under the flywheel and the red ones to what looks like a celonoid and directly connected to the battery. I was actually hoping I had the cheaper regulator, but I guess the more expensive one is easy enough for me to change, it looks hot-swapable...<br /><br />Any help is still appreciated!!!

 

[thewatercallsme]

Re: 1996 Mariner 150HP Overcharging Batt 16.5Volts

I'm begging for help, what are the prices and which direction should I go in troubleshooting???

 

[chuckz]

Re: 1996 Mariner 150HP Overcharging Batt 16.5Volts

It sounds like the two modules you are looking at are the ignition modules. Before you do anything else disconnect and clean all you electrical connection ESPECIALLY the ground wires. Tighten the battery connections. Confirm the voltage with a voltmeter.

 

[Valv]

Re: 1996 Mariner 150HP Overcharging Batt 16.5Volts

If you get your motor serial # and look at Mercury Parts Express page, it will have all the part schematics for your motor, you can see where everything is and also check prices.<br /><br />The site is:<br /> http://www.mercurypartsexpress.com/PartsExpress/ProductSelection/ServiceParts/sphome.asp?CID= <br /><br />Also if you look on the famous online auction site there are some new for $ 20/$30<br /><br /> http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&category=50439&item=4530373216&rd=1