What is charging voltage for Mercruiser 3.7 eng.

[ElectraGlide H2O]

Two weekends ago I purchased a 1989 Wellcraft with Mercruisers 3.7 engine. All seemed well until this weekend when I installed a fish finder. While I was running down the lake I got a message on the fish finder that input voltage was too high . This caused me to pay attention to my in dash volt meter. Under acceleration and even at times while idling my volt meter shows that it is charging at 16 to 17 volts. Is my voltage regulator gone bad? This seems high to me. I wonder if dash gauge is even correct because fish finder is supposed to work from a 10 to 20 volts power source. Help! Any suggestions???

 

[Eric 3.7LX Alpha 1]

Re: What is charging voltage for Mercruiser 3.7 eng.

yes it's toast, voltage that high can kill your electronics and batteries.

Best advise and mutual from most on here will be to replace it with a belt driven marine alternator. You can buy complete conversion kits on ebay, or breezeworks.net, or make the brackets yourself if you are crafty.

Keep a very good eye on your temp gauge. If the 3.7 ever overheats it will be new head gasket time.

 

[wrestling coach]

Re: What is charging voltage for Mercruiser 3.7 eng.

I went through the same issue at the beginning of this boating season. I converted to the Breezeworks kit. They have high mounts or low mounts with or without power steering. Everything you need is in the kit. Easy swap. Move on from the stator/regulator system.

Dennis

 

[stonyloam]

Re: What is charging voltage for Mercruiser 3.7 eng.

++ to both guys, your voltage regulator is shot. Breezworks is where I went for mine too.

 

[Jlawsen]

Re: What is charging voltage for Mercruiser 3.7 eng.

The voltage regulator is probably shot now but it was more than likely a bad ground that caused the alternator to not see the proper load and spike. Those voltages you were seeing are typical of when a ground (negative battery connection) is missing, loose, corroded, etc. It's also typical of when someone disconnects a battery negative connection while the engine is running.

 

[ElectraGlide H2O]

Re: What is charging voltage for Mercruiser 3.7 eng.

Thanks to all for your input and advise. Dang my very first post to this forum and its going to cost me $300. Ha! Ha! Seriously I was afraid that the voltage regulator was toast. I will check tomorrow for any lose grounds and then most likely place an order with Breezeworks for their conversion kit. I know this is going to sound stupid but what is the difference between the low mount and high mount kits. I assume that it is exactly what it says but is this a matter of preference or is there clearence issues that force you to use one or the other. Thanks again to all ....Kenny

 

[achris]

Re: What is charging voltage for Mercruiser 3.7 eng.

If you have room for the high mount, go for that one... Best try and keep electricals out of the bilge... :facepalm:

Chris.....

 

[ElectraGlide H2O]

Re: What is charging voltage for Mercruiser 3.7 eng.

Thanks Chris, After looking at the pictures at Breezeworks.net of the high mount alternator it appears that after being added is still not the highest part of the engine nor is it the most forward part towards the bow. I think it should work for me.

 

[stonyloam]

Re: What is charging voltage for Mercruiser 3.7 eng.

If you have power steering, you want to go with the low mount. Otherwise the high mount is OK. Here is my low mount with P/S:

 

[wrestling coach]

Re: What is charging voltage for Mercruiser 3.7 eng.

Here is a low mount without power steering.

Dennis

 

[Faubertlx]

Re: What is charging voltage for Mercruiser 3.7 eng.

I have the same motor, all my electronics are working fine but i have been hearing that the charging system will go out eventually so im just going to order the alternator kit tomorrow

 

[nola mike]

Re: What is charging voltage for Mercruiser 3.7 eng.

I went with the low mount kit because it looked like a more robust setup and seemed less in the way. As for being low near the bilge, if the water gets that high, I've got other problems...

 

[ElectraGlide H2O]

Re: What is charging voltage for Mercruiser 3.7 eng.

Thanks for the great picture wrestling couch/Dennis the makes the picture a whole lot clearer...no pun intended. I just got an email back from Kevin this evening and he suggested the high mount for my boat. I checked things out this evening and it appears that the high mount will clear everthing just fine. I guess I will go ahead and put my order in the morning. Thanks everyone for your participation!!