Older boat alternator upgrade on the cheap

[UWSkier]

https://www.amazon.com/gp/product/B07JGL3SPQ/ref=ppx_yo_dt_b_asin_title_o03_s00?ie=UTF8&psc=1

 

I used one of these for the bolt.  M8 bolt worked.

Ground wire terminates on a stud right above the starter screwed into the engine block.

Edited July 6, 2020 by UWSkier

[drh]

@UWSkier So you weren't able to use the factory bottom bolt for the replacement alternator? I'll be doing the swap this weekend and want to be sure I have everything I need.

[footndale]

On 5/16/2020 at 4:35 PM, UWSkier said:

If you have a 2002 or older Indmar and are still running the original alternator, there's a cheap upgrade path if you're so inclined.  I wanted more juice because PerfectPass, a heater running on high, a circulation pump, and a blower motor running was a bit more than my old alternator was happy with to give enough extra charge to feed the battery.  So, I went with this.

https://www.dbelectrical.com/products/marine-alternator-crusader-pleasurecraft-5-0-5-7-litre.html

and one of these

https://www.ebay.com/itm/New-Alternator-Repair-Harness-fits-Delco-5SI-7SI-Marine-Alternators-19020601/273250473079?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2060353.m2749.l2649

and got to work.  It's a pretty simple job to swap out.

First, remove old alternator.

Second, install new alternator.

Third, run an additional wire from the alternator + to the + stud on the starter, being careful to run the wire in a manner that it can't rub and ground out on the engine block over time.

Fourth, optionally run an additional wire from the alternator - to the - stud on the engine block.

Fifth, cut off the ring connector on your purple wire and solder the purple wire to BOTH LEADS from the pigtail.  Use heat shrink on all of your connections.

Result: Whereas my old alternator was only good for about 13.3-13.4v at the dash at idle with no additional load, this one gives me a nice solid 14.0v.  Before, when I'd switch everything on, my voltage would drop to a bit over 12.7.  With this one, the voltage regulator compensates for load and bumps up output to match the demand.  I can turn on every electrical accessory I've got and my voltage stays pegged at 14.0v.

Need pics. 

I was told last week not to run all the controls on the Sunsetter LXI 99, while idle. Some gauges my not work properly. First time I have ever heard this. I bet this might help though.

[UWSkier]

2 hours ago, drh said:

@UWSkier So you weren't able to use the factory bottom bolt for the replacement alternator? I'll be doing the swap this weekend and want to be sure I have everything I need.

My bottom bolt was sheared off so I needed a new one anyways.  TBH I think the original would have worked if it wasn't sheared off.  According to the Indmar parts manual, it's a M8x1.25 bolt so that's what I ordered and it worked great.  I couldn't find a match at my local Home Depot.  Maybe if I'd tried an ACE, but this was at the height of the pandemic scare so I just Prime'd the ones from Amazon and called it good.  I have 9 extra ones now.  lol

[UWSkier]

1 hour ago, footndale said:

Need pics. 

I was told last week not to run all the controls on the Sunsetter LXI 99, while idle. Some gauges my not work properly. First time I have ever heard this. I bet this might help though.

I can try to get pics later but there's really not much to it at all.  I'd check all grounds on that 99 first though, and run a fused + lead from the battery straight to the positive bus bar and a heavier - straight from the ground bus to the battery.  In 99, the power to the entire dash came from the cannon plug connection (something else to check and dialectric grease).  Sometime in '01 they made a running change to fix that.

[UWSkier]

part number 107 in this diagram is where I got the thread pitch info.  My alternator bracket is the older style that screws in from the back though so I went with the longer bolts at the amazon link I included above.

[drh]

Ok I assume mine is similar to yours then. The top bolt slides to tighten and the bottom bolt is the pivot and screws in from behind. Also, V belt not serp.

[UWSkier]

1 hour ago, drh said:

Ok I assume mine is similar to yours then. The top bolt slides to tighten and the bottom bolt is the pivot and screws in from behind. Also, V belt not serp.

Same setup.

[CraigSim]

On 7/7/2020 at 1:56 PM, UWSkier said:

part number 107 in this diagram is where I got the thread pitch info.  My alternator bracket is the older style that screws in from the back though so I went with the longer bolts at the amazon link I included above.

I wanted to replace these bolts with stainless steel. Does anyone see a problem with that? I'm not sure why bracket bolts needed to be graded (at least mine are grade 5 bolts). 

[CraigSim]

Also, great topic and thread!

Was just looking to replace the alternator in my 2000 Response. Was blown away that is was over $300 on Bakes...and without the pulley. I will definitely be doing this. Already ordered the parts.

[CraigSim]

For those who saw my question about SS bolts instead of the original bolts, I search around and found a car blog that talk about good engine bolts that are stainless steel. It was also mentioned to use anti-seize if you go this route due to the different metal types. They are a little pricey, but seem to be strong and good quality. They come from ARP - https://arp-bolts.com/

You can also find them on Amazon. Think I am going to give it a try. It will look pretty sweet. 

[Woodski]

ARP has an excellent selection of fasteners.  A go to source for racing applications, many engine builders, etc.

[cowwboy]

I put the same one in my boat a few weeks ago. 

Their test sheet showed it outputting over 90 amps  (70 amp rating). 

So I of course had to test their results. I grabbed my fluke clamp on amp meter and a heat strip battery tester. With my engine at 2500 rpm and using a 100 amp draw battery tester I got a output of 97 amps off the alternator. 

I can't really weigh in on the voltage drop due to my boat running a golf cart based battery bank so it doesn't drop much under load. 

 

So for the price and all new not rebuilt it's a hard alternator to beat. 

 

[justgary]

On 7/13/2020 at 9:43 AM, CraigSim said:

It was also mentioned to use anti-seize if you go this route due to the different metal types.

Aviation Shellac (such as Permatex 80019) is possibly a better alternative.

[Newcomer]

Hey UWSkier, I need some clarification on this.  You are helping me with another maybe related electrical issue/post.  I am getting ready to do this alternator upgrade to 2001 Wakesetter.  What I found is someone put a rebuilt car parts store alternator on my boat, cut the original wire harness and wired this rebuilt alternator to the flat style two wire gm connector.  The heavy orange original wire goes to the single terminal and then to starter, I get that.  The last person cut the purple wire and joined it to now white wire of flat connector.  The red wire from the flat connector is not connected to anything.  Then there is a black ground.  My question is since the original is gone, what was the original wiring.  I have an orange, purple, black coming through the original harness to the alternator.  If I use this upgraded alternator with the oval two wire connector, the purple wire connects to both?  Also, I'm reading related posts that talk of not being able to cut the engine off.  I tried this with this rebuilt alternator because some people put the sense wire back to the hot stud on the alternator.  I also could not cut the engine off, without pulling the coil wire, so the wire is not connected.  What was the original Indmar hookup for these three wires going to four terminations.  Please help, thanks

Edited August 10, 2020 by Newcomer

[UWSkier]

53 minutes ago, Newcomer said:

Hey UWSkier, I need some clarification on this.  You are helping me with another maybe related electrical issue/post.  I am getting ready to do this alternator upgrade to 2001 Wakesetter.  What I found is someone put a rebuilt car parts store alternator on my boat, cut the original wire harness and wired this rebuilt alternator to the flat style two wire gm connector.  The heavy orange original wire goes to the single terminal and then to starter, I get that.  The last person cut the purple wire and joined it to now white wire of flat connector.  The red wire from the flat connector is not connected to anything.  Then there is a black ground.  My question is since the original is gone, what was the original wiring.  I have an orange, purple, black coming through the original harness to the alternator.  If I use this upgraded alternator with the oval two wire connector, the purple wire connects to both?  Also, I'm reading related posts that talk of not being able to cut the engine off.  I tried this with this rebuilt alternator because some people put the sense wire back to the hot stud on the alternator.  I also could not cut the engine off, without pulling the coil wire, so the wire is not connected.  What was the original Indmar hookup for these three wires going to four terminations.  Please help, thanks

Purple wire comes from the ignition.  It's used to "excite" the alternator.  In alternators with a sensing function, it also provides a reference potential to tell the voltage regulator how much juice to pump.

Wiring of this alternator I installed is as follows.

Orange + to + stud on starter.  I recommend a piggy-back heavier gauge wire to be added in parallel to this particular run.

Black - to - stud on the engine block.  Again, I piggy-backed an additional wire here for any extra current.

Purple wire you need to cut whatever's on there off and solder BOTH wires from the pigtail in my OP to that wire.  One of these is the exciter, and the other is the voltage reference.

You could instead jumper the sense wire right to the + terminal, but you won't get any compensation for voltage drop that way.  It'll be "seeing" the remote voltage as that what's coming right off the alternator rather than what's being delivered to the dash.

[Newcomer]

If the sense wire is jumpered to the + terminal the boat won't cut off.  Do you know why this happens?  Will this happen if both of the connector wires are connected to ignition purple? Thanks

[UWSkier]

Because the exciter wire needs 12v going into it to offset the 12v it's trying to push back in the other direction.  Absent this, even when you shut off the ignition, there's a 12v source on the "run" post on the keyswitch.  You can get around this by wiring in a diode.

But wire it the way I said to.  It's the "official" way Indmar recommends you wire it if you buy their upgrade kit.

[Newcomer]

Is this the way it would have been wired originally? The purple wire from the harness connecting to both pins of the original alternator?  And the hot wire (orange) from + to the starter. Thanks

[UWSkier]

hot wire to starter, yes.  Purple wire connected to an exciter post on the original alternator.  Original alternator is a 3 wire setup.  The alternator in this setup is a 4 wire setup but two of those wires go to only the purple wire.

Reference voltage on this alternator is 14.0v.  That's bang on what I get at idle or any RPM with this thing.  My battery has never been happier.

Edited August 11, 2020 by UWSkier

[BlindSquirrel]

@UWSkier What gauge wire did you use for those additional + and -? Getting ready to upgrade my 98. Thanks.

[UWSkier]

1 hour ago, BlindSquirrel said:

@UWSkier What gauge wire did you use for those additional + and -? Getting ready to upgrade my 98. Thanks.

Think it was 2awg but I could be wrong.  I actually used repurposed wiring that was originally part of a kit that ran an electric boat lift motor off the boat battery.  It's heavy duty stuff.  Similar to amplifier power wire.

[BlindSquirrel]

On 4/14/2021 at 2:20 PM, UWSkier said:

Think it was 2awg but I could be wrong.  I actually used repurposed wiring that was originally part of a kit that ran an electric boat lift motor off the boat battery.  It's heavy duty stuff.  Similar to amplifier power wire.

One more question....thank you for your help on this. Did your alternator come with a grounding nut? Unless I take off the one that is already there and use it to hold the ground on. I assume this is the grounding post. 
 

 

[UWSkier]

Yes that's the post ground and no it didn't come w a second nut like the + post did. 

[RiversMalibu]

A great thread. I’m going to do this soon. My alt went out this weekend. I have a 97 tantrum with the 320 monsoon. The alt is a rebuilt Ultima alternator. I’m assuming since rebuilt it’s not factory. Hoping the wiring is simple as you made this sound. I think they have already modded it a bit. There is a pigtail on this one.