Battery question

smoothsailing · Jun 9, 2008

Mercruiser 170 installed in a 1986 Wellcraft 192 American. I dont run any electronics (radios, fish-finder, etc).

Silvertip said:
You DO NOT want deep cycle batteries for starting batteries. House batteries require deep cycle. Starting batteries must be marine starting batteries. Just so you understand the terminology, and engine that turns over by the starter = cranks or turns over. An engine that turns over or cranks but doesn't start = cranks but doesn't start.

Just so I understand this correctly... The minimum battery requirements are 450CCA / 90 Ah.

I have put in an Everstart MAXX Marine Max29 875MCA / 205 Reserve Cap. Says it serves trolling, starting, etc. But since I am not running any electronic devices, I am supposing I should get a "Starting" Battery instead? After a full days boating, my last few starts are real load on the battery, and I am wondering if this is it?

Don S · Jun 9, 2008

Re: Battery question

Any 24 series starting battery will work great for your 470 type engine.
Any battery even the dual purpose batteries will start that motor unless you have to do a LOT of excessive cranking to get it started. Shouldn't have to crank over more than 5 or 6 revolutions before it starts, if tuneup up properly, the carb is adjusted, and you use the proper technique to start a carbed engine.
You mentioned that after a full day of boating the last few starts are a load. Sounds to me like a low battery. Have you checked the charging system to see if it's working properly? The 470's were known for charging problems.

Bondo Again · Jun 9, 2008

Re: Battery question

The 470's were known for charging problems.

Ayuh,..... You ain't got a Battery Problem,....

Your Charging System is Whooped.....

Those old 470s have a water cooled voltage regulator that ca be a Problem.....
Or,... The Magnets at the Crankshaft....

smoothsailing · Jun 9, 2008

Re: Battery question

Now I'm leaning toward the charging system then.. as the battery is whooped by days end. Wish someone was making those regulators (99502A12) for less than 400 bones. Thanks for your replies, 'twas a big steer in a better direction.

Don S · Jun 9, 2008

Re: Battery question

There are aftermarket kits to change over from that rotor/stator, watercooled regulator outboard wanna be charging system. Usually less than the regulator alone, and available, unlike other parts in that charging system.

CharlieB · Jun 10, 2008

Re: Battery question

Are you running a trolling motor and fishing part of the day?

smoothsailing · Jun 10, 2008

Re: Battery question

No trolling. Mostly stop and go tubing, and lounging around the lake.

smoothsailing · Jun 10, 2008

Re: Battery question

On that note of voltage regulators... I whipped out the manual and went searching down the troubleshooting steps for the Voltage regulator. I'm having some difficulty locating it. Here is my layout

And here is a layout of another type..

Am I off the mark here... or does mine have an alternator on that front belt? And hence, no Voltage regulator (modded already???)

smoothsailing · Jun 10, 2008

Re: Battery question

More Pictures.. if it'll help.

Don S · Jun 10, 2008

Re: Battery question

You won't have to worry about the oem charging system, you have an alternator kit already installed and the regulator already removed.
When you start it up, put a DVM on the battery before you start and measure the voltage. Start it up and run it about 1200 rpm and see what the voltage is then.

bhammer · Jun 10, 2008

Re: Battery question

What Dons said. The voltage regulator, if not removed as in your case, is on the port side, toward the front. It is bolted onto the block right under the water heat exchanger. It's about 3" or 4" square.

The good news is that you can pick up those style alternators in the marine version for a good price or have them rebuilt.

smoothsailing · Jun 12, 2008

Re: Battery question

Don S said:
You won't have to worry about the oem charging system, you have an alternator kit already installed and the regulator already removed.
When you start it up, put a DVM on the battery before you start and measure the voltage. Start it up and run it about 1200 rpm and see what the voltage is then.

Thanks Don (and everyone else contributing).. I'm heading out tomorrow to the lake to do some troubleshooting, and as I wont have access to the forums during this period....

Check voltage prior to and during 1200rpm range.. if all is well, then should I check current from alternator to battery? (I'm trying to get a few steps ready as it's 45mins between house and boat). I'm assuming that the charging from the alternator is a simple 1-wire outfit.

Thanks in advance, I wish I was more mechanically inclined to not have to ask what may seem stupid questions.

Bondo · Jun 12, 2008

Re: Battery question

Check voltage prior to and during 1200rpm range..

Ayuh,....

Just Check the Voltage, Before you start the motor,... It should show 12V to 12.6V....
Then start the motor,.... At anything over Idle,... It should show 13.6V or slightly More....
If it Doesn't,... Look for broken wires as you pull the alternator, to have it Tested by a Electrical Shop.....
If you find a Broken Wire,... Fix it,+ Retest....
If not,.... Bring the alternator to a repair Shop....Or Replace it...

smoothsailing · Jun 15, 2008

Re: Battery question

12.65 before start... 12.35 after 1000-1200 rpm... alternator (1-wire) showing no voltage other than battery voltage.. one alternator on order. Thanks for the help on this one folks, I'm more educated that 1 week ago...

At least this will give me time to put some Danish oil on my teak.

Battery question

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