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swatguy
10-04-2011, 08:27 PM
So I toasted yet another Alt. Something tells me its just not bad luck anymore. I am not shredding belts or even showing a mark on a belt. The original/ upgraded one that the prior owner had boosted up was 90 amps. I went through 2 rebuilds from 2 dif places. One lasted 2mos. The other 4 and then I decided to just go new. Well now the new one has toasted as well. The first one locked up and the cooling fan blew apart. All of them seem to just melt/fry. Smell like burning metal.

The new one I bought was a remy/delco. 70amp. Dealer said it was the match to the original.

I have dual battery and a small system with 2 amps. Can't believe that is frying it as I barely run the hard at all. Any ideas on where to start or if it is just string of bad luck.

mikeg205
10-04-2011, 08:57 PM
Sounds...seems like maybe the belt it too tight? how are you measuring belt tension?... I used to blow water pumps in my car till i got the belt tension right.... when snug when you press in the belt it should deflect up to a half inch. Anyway have take it apart and see what's fried.. if it just locked up...belt most likely too tight...

swatguy
10-04-2011, 09:01 PM
I have the Ltr so it has tensioner pully. I replaced that as well after 2nd rebuild. Just the first one locked up. The rest his melt/fry.

JimN
10-04-2011, 09:22 PM
So I toasted yet another Alt. Something tells me its just not bad luck anymore. I am not shredding belts or even showing a mark on a belt. The original/ upgraded one that the prior owner had boosted up was 90 amps. I went through 2 rebuilds from 2 dif places. One lasted 2mos. The other 4 and then I decided to just go new. Well now the new one has toasted as well. The first one locked up and the cooling fan blew apart. All of them seem to just melt/fry. Smell like burning metal.

The new one I bought was a remy/delco. 70amp. Dealer said it was the match to the original.

I have dual battery and a small system with 2 amps. Can't believe that is frying it as I barely run the hard at all. Any ideas on where to start or if it is just string of bad luck.

What amps do you have? How old are the batteries, and are they the same type (both cranking batteries, or one cranking battery and one deep-cycle battery)? How low do you discharge them, has the cranking battery ever gone dead and then you started it by jump starting and letting the alternator re-charge it?

swatguy
10-04-2011, 11:44 PM
Both batteries are deepcycle.. and are a season old. Not sure off hand but think they are 24 group. The stereo battery was drained down to 11.2 volts one time but then immediately hooked to charger. Both batter read 12.4v when at rest. I am running a Wetsounds Syn 2 and Wetsounds Syn 4 amp. Of the time the stereo spends on maybe 10% is while boats not running.

I did notice the previous owner taped off the original purple n black harness and it now has single lead to alt consisting of power wire..

The delco/rent I have is 12v 70amp grd neg
19020606

swatguy
10-04-2011, 11:45 PM
Battery was never so dead it didn't start and had never been jumped

Jerseydave
10-05-2011, 03:51 AM
My buddy has an '01 X-star and water drains from the sunpad right onto the alternator. He buys a new one every year. Trying to devise a tray to keep the water from pouring onto the alternator. (salt water)

Either that or you're just having some bad luck. Do you have a lot of amps on your sound system? Maybe the alt is being worked too hard?

MCfreak227
10-05-2011, 05:56 AM
First of all a deep cycle battery is not designed to be charged by an alternator. The lead plates in a deep cycle battery are a lot thicker than your standard cranking battery and are harder for the alternator to charge. A deep cycle battery is designed to go through many repeated full charge and full discharge cycles (i.e. A 12v or 24v trolling motor). A starting battery is designed to be discharged slightly then recharged by the alternator (i.e. starting your engine then allowing the alternator to replace voltage used in starting).

"Battery was never so dead it didn't start and had never been jumped" This leads me to believe that your alternator is "over charging" because when an alternator typically goes bad it stops producing voltage that is feeding the battery and ignition and then the engine dies after the ignition has used up the voltage in the battery and the battery will be stone cold dead. So if your frying alternators and have not had to charge your battery I instantly think "over charging"


An alternator has an internal voltage regulator which is controlled by increasing or decreasing resistance within the charging circuit depending on what kind of electrical demand is on your charging system at that time. So if you are consuming a lot of voltage with your stereo the voltage regulator is not placing any resistance in the circuit. If you are consuming little or no voltage and your starting battery is fully charged then the voltage regulator places heavy resistance in the circuit and discharges to ground to keep from not only working the alternator itself too hard but also to protect all electrical circuits from seeing too much amperage/voltage

SOOO... how does the alternator know how much amperage to push out?
That would be from the "Sense Circuit" which include the PURPLE and BLACK wires you noticed that are taped off. Without that "Sense Circuit" the alternator is constantly working as hard as it can no matter if your stereo is off or full blast because there is no way for the voltage regulator to place resistance on the charging circuit and the alternator thinks it needs to work its butt off all the time which eventually results in premature failure

From constantly working so hard your alternators are not lasting very long...You can confirm this issue by either looking at your voltage gauge while the engine is running or observing a reading from an electrical multimeter that is set up to read voltage across the battery while the engine is running. While looking at either of these instruments if you see anything above approx 14.5V-15v then your system is "over charging" and you would begin your repair of the "Sense Circuit"

Go grab yourself a wiring diagram and start tracing those PURPLE and BLACK wires and make sure the wires themselves are not damaged or chaffed anywhere that they could be shorting to ground and that all connections are clean and tight...obviously there's a reason why they are not currently hooked up

After confirming the correct wire locations and good condition of the "Sense Circuit" reconnect them to their appropriate places on the back of the alternator and perform your voltage test again to confirm proper charging which should be approx 13.5v-14.5v depending on current battery voltage.


Hope this helps let me know whatcha find!

R. Collins

CantRepeat
10-05-2011, 06:53 AM
Both batteries are deepcycle.. and are a season old. Not sure off hand but think they are 24 group. The stereo battery was drained down to 11.2 volts one time but then immediately hooked to charger. Both batter read 12.4v when at rest. I am running a Wetsounds Syn 2 and Wetsounds Syn 4 amp. Of the time the stereo spends on maybe 10% is while boats not running.

I did notice the previous owner taped off the original purple n black harness and it now has single lead to alt consisting of power wire..

The delco/rent I have is 12v 70amp grd neg
19020606

:noface: That's just bad right there. You're going through alternators left and right because the charging system wiring is screwed up. Fix this first and your problems would be solved.

JimN
10-05-2011, 08:07 AM
Both batteries are deepcycle.. and are a season old. Not sure off hand but think they are 24 group. The stereo battery was drained down to 11.2 volts one time but then immediately hooked to charger. Both batter read 12.4v when at rest. I am running a Wetsounds Syn 2 and Wetsounds Syn 4 amp. Of the time the stereo spends on maybe 10% is while boats not running.

I did notice the previous owner taped off the original purple n black harness and it now has single lead to alt consisting of power wire..

The delco/rent I have is 12v 70amp grd neg
19020606

Why do you use a deep cycle battery for cranking? What's the CCA rating? Your starter draws a lot more than deep cycle batteries are designed to provide and that means it takes longer to recharge. Taking longer makes the alternator get hotter and stay hotter, which kills it faster. 12.4 at rest is low.

If the alternator doesn't need the purple wire, it just means that it doesn't need the exciter wire. Hopefully. If the new one is the OEM type your boat had, it will need this wire.

swatguy
10-05-2011, 03:25 PM
So first off let me apologize for getting the battery wrong. I recently bought new batt for my bass boat and it was deep cycle.

My boat batts are both Interstate 24m xhd batteries with 1000 cranking amps and a 135 reserve. Talked with guys over at the alt shop. They said there should sec be more than one wire and said that one of those wires should plug into the alt so that it gives. feedback to the alt about battery voltage.

I had wires that were taped off. One is purple and the other is black, both with ring terminals Guessing the purple is related to ignition. Those are only other free wires back there. They said most likely frying due to the alt not receiving feedback from batteries on how charged they are so its running at full blast constantly heating up in laymans terms.
J

Hopefully indmar warranties the alt that's 7mos old

CantRepeat
10-05-2011, 04:12 PM
Maybe it's possible for someone with the same boat and motor to post up a photo of their alt wiring for you?

swatguy
10-05-2011, 04:41 PM
It was brought to my stymied that these alts are single wire capable and dont need that excite/ignition attached. It has an internal regulator.


However the alt guys suggested I grab a tsc200 from Napa to attach the excite. So now I am confused even more.

thatsmrmastercraft
10-05-2011, 05:09 PM
So first off let me apologize for getting the battery wrong. I recently bought new batt for my bass boat and it was deep cycle.

My boat batts are both Interstate 24m xhd batteries with 1000 cranking amps and a 135 reserve. Talked with guys over at the alt shop. They said there should sec be more than one wire and said that one of those wires should plug into the alt so that it gives. feedback to the alt about battery voltage.

I had wires that were taped off. One is purple and the other is black, both with ring terminals Guessing the purple is related to ignition. Those are only other free wires back there. They said most likely frying due to the alt not receiving feedback from batteries on how charged they are so its running at full blast constantly heating up in laymans terms.
J

Hopefully indmar warranties the alt that's 7mos old

Sounds like you need a wiring diagram, or a pic as someone else suggested. Are you really going to try to get Indmar to try to warranty an alternator that you cooked? Hate to see a guy with boat problems, but....

swatguy
10-05-2011, 06:43 PM
The alt is brand new and it was installed by my dealer. It has a warranty so yes I will try and have it covered under warranty by Indmar. What wouldn't I? That's what a warranty is for. I didn't cook it by installing it wrong or short it out somehow by my actions, the boat did. That's what I am trying to figure out.

thatsmrmastercraft
10-05-2011, 07:28 PM
The alt is brand new and it was installed by my dealer. It has a warranty so yes I will try and have it covered under warranty by Indmar. What wouldn't I? That's what a warranty is for. I didn't cook it by installing it wrong or short it out somehow by my actions, the boat did. That's what I am trying to figure out.

Both batteries are deepcycle.. and are a season old. Not sure off hand but think they are 24 group. The stereo battery was drained down to 11.2 volts one time but then immediately hooked to charger. Both batter read 12.4v when at rest. I am running a Wetsounds Syn 2 and Wetsounds Syn 4 amp. Of the time the stereo spends on maybe 10% is while boats not running.

I did notice the previous owner taped off the original purple n black harness and it now has single lead to alt consisting of power wire..

The delco/rent I have is 12v 70amp grd neg
19020606

I don't mean to be insensitive to your alt problems. I'm sure you have laid out a pile of cash, and correct me if I'm wrong, but didn't the previous owner cause the problem? I could see going after the dealer for not properly testing the charging system after installing an alternator and putting them on the line for the loss of the alternator, but Indmar supplied a properly functioning alternator if I read this all correct.

As a side note, I would think that your battery life will be significantly shortened by "cooking" them so much.

Good luck with sorting this problem out. The PO of my boat repowered it and did all sorts of cutting and splicing, so I feel your pain.

CantRepeat
10-05-2011, 08:03 PM
The alt is brand new and it was installed by my dealer. It has a warranty so yes I will try and have it covered under warranty by Indmar. What wouldn't I? That's what a warranty is for. I didn't cook it by installing it wrong or short it out somehow by my actions, the boat did. That's what I am trying to figure out.

I wouldn't know which way to go on this, really.

I mean, the alt warranty from manufacture is going to be void based of an improper install. Who's at fault for that? The people that installed it I would think, not Indmar.

swatguy
10-05-2011, 08:12 PM
No worries at all.

That's my point exactly. When I blew the 2nd refurbished one I figured it was something incorrectly wired. I then took it to my dealer and had them check it replace both batts and install the new one. They left the wires taped up and put the new one on. They explained the alt has single wire capabilities and that's y no need for others. However i have owned boats for long time, was a rep for another company. I have seen my fair share of dealer mishaps on repairs. That is why I am here trying to educate myself and fig it out with aid of some fellow members before I resort back to the dealership.

I have had the boat for 6 seasons and the first 3.5 didn't see one roasted alt. The only thing in my stereo/ electrical that has changed would be the tower speakers and one of my amps, but that changed after my new alt. So had the problem beforehand.

JimN
10-05-2011, 08:37 PM
So first off let me apologize for getting the battery wrong. I recently bought new batt for my bass boat and it was deep cycle.

My boat batts are both Interstate 24m xhd batteries with 1000 cranking amps and a 135 reserve. Talked with guys over at the alt shop. They said there should sec be more than one wire and said that one of those wires should plug into the alt so that it gives. feedback to the alt about battery voltage.

I had wires that were taped off. One is purple and the other is black, both with ring terminals Guessing the purple is related to ignition. Those are only other free wires back there. They said most likely frying due to the alt not receiving feedback from batteries on how charged they are so its running at full blast constantly heating up in laymans terms.
J

Hopefully indmar warranties the alt that's 7mos old

The black wire is the ground wire for the internal voltage regulator on the OEM alternator and the purple wire energizes the field coil in the armature, which is used to generate AC voltage. The AC is rectified to DC voltage and regulated internally, with the battery doing the rest of the filtering. It's not "feedback from the batteries, it's where the alternator gets its magnetic field, used to generate voltage. If the purple wire is pulled off, it will only cause the alternator to stop producing voltage. If the charging lead is too small, the batteries won't be fully charged and that places a constant load on the alternator. That's probably why you keep going through alternators- the batteries never charge fully and the alternator never gets a break. If the alternator is upgraded to a higher output model, the charging lead should have been upgraded to a gauge that would support the output current plus about 25%, as a safety margin.

JimN
10-05-2011, 08:40 PM
It was brought to my stymied that these alts are single wire capable and dont need that excite/ignition attached. It has an internal regulator.


However the alt guys suggested I grab a tsc200 from Napa to attach the excite. So now I am confused even more.

The first statement is dead wrong- the OEM alternator had a purple wire for the field and an orange or red charging lead, possibly with a black ground wire. If you were to call MC or Indmar for the OEM part number and look at it, you would see the same alternator I have in my Chevy pickup.

swatguy
10-05-2011, 09:44 PM
So Jim are you saying I need to hook those up to the 70amp alt? trying to fig out a diagram for the proper alt wiring. Called my tech at the dealer he stated wasn't needed. While I am not arguing I am just trying to understand all the conflicting info and how things work. I called 3 dealers today and each gave me a little dif answer over the phone with wiring.

As u were mentioning the gauge size for the lead..........That is one of the first things that came to my mind. Any gauge in particular I should be considering?




I also want to thank everyone so far for their help and input so far.

JimN
10-05-2011, 10:56 PM
So Jim are you saying I need to hook those up to the 70amp alt? trying to fig out a diagram for the proper alt wiring. Called my tech at the dealer he stated wasn't needed. While I am not arguing I am just trying to understand all the conflicting info and how things work. I called 3 dealers today and each gave me a little dif answer over the phone with wiring.

As u were mentioning the gauge size for the lead..........That is one of the first things that came to my mind. Any gauge in particular I should be considering?




I also want to thank everyone so far for their help and input so far.

No, you don't need to use an alternator of any specific amp rating. What you need is someone who knows how the OEM alternator is supposed to be wired. If the original had been replaced before you bought the boat, that's one thing but if it went bad after you bought it and there was no real reason to replace it with another style, it should have been replaced with an identical model/part number or rebuilt to the same, or the highest available specs for that case. Your alternator can be rebuilt to 95 Amps, according to the shop where I buy reman alternators and starters. Your OEM alternator had a purple wire, as I posted. MC has used that style of alternator since they started working with GM engines and that's because they work. It can't draw any current unless the key is turned to ON or the bridge rectifier goes bad. BTW- the easiest way to kill a bridge rectifier (that's what converts the AC voltage to DC) is by jump starting a motor with a dead battery when the engine connected to the donor battery is still running. The instantaneous current draw from a starter is far more than 70A or 95A- it's in the range of 150A-350A.

If you can, post a photo of the old and new alternators. If you have the OEM type now, you definitely need the purple wire to be connected. The alternator can't generate any voltage if it's not.

If you really want to know how this boat was wired, call MC or Indmar and ask for a diagram AND the OEM part number for the alternator.

swatguy
10-05-2011, 11:37 PM
Jim.

I bought the boat with an upgraded 70 amp alt installed. So from day one of my ownership the purple wire and black wire were taped off. When I had them rebuilt the shop said they could boost it to around 90 as you stated due to limits. Since day one of my ownership with the upgraded alt it kicked on around 1500rpms. I had to rev it just a bit. This is what was explained to me why I didn't need the exciter. These alts were single wire. These are the only alts I have ever had on the boat since my ownership. I never had the original 55amp. So my wires were taped off since day one of my ownership.

swatguy
10-11-2011, 01:04 AM
Ok so here we go.

Got the replacement alt from indmar. They said the 70amp I had was the correct upgraded alt. The also said the alt is a single wire alt and will work off the one terminal unlike the original 55 amp one. It doesn't need the excite as it is designed to kick on at around 1600rpms. So in order to get it kicking it have to rev it a bit after start.

Off the digital voltage reading from my distribution block after the install my readout was 15 at the higher idle and cruising around at 15-20mph. My batts are 12.7. I now have my hands n a voltmeter and will try and get an amp meter. Looking for some info on where to get started on checking.

CantRepeat
10-11-2011, 06:18 PM
You gotta ask yourself, why am I replacing 4 altenators in 2.5 years?

There has to be something wrong with your setup. No one goes through that many alt without some other underlying issue. No one. :confused:

oldairboater
10-12-2011, 11:23 AM
I would figure out my amperage draw in that boat. Some of the sound systems I have seen are big amp draws. I run single wire 90amp alternators in my other boats. They do not load up till rpm gets close to 2000. The only issue I have ever had with them was cheap bearings. I run dual batteries minimum and there is always multiple light draws when running before daylight. I am not a fan of trickle chargers--we refer to them as battery cookers. With that said I always put a battery charger on slow charge and connect it to any boat I am taking out the day before we need the boat. Load, water, and heat kill alternators. Ok so here we go.

Got the replacement alt from indmar. They said the 70amp I had was the correct upgraded alt. The also said the alt is a single wire alt and will work off the one terminal unlike the original 55 amp one. It doesn't need the excite as it is designed to kick on at around 1600rpms. So in order to get it kicking it have to rev it a bit after start.

Off the digital voltage reading from my distribution block after the install my readout was 15 at the higher idle and cruising around at 15-20mph. My batts are 12.7. I now have my hands n a voltmeter and will try and get an amp meter. Looking for some info on where to get started on checking.

swatguy
10-12-2011, 12:55 PM
So made some progress on the situation. Took some calls to several dealerships as well as Indmar and skidim.

While the kit from ski dim says the harness is not needed it is needed so not sure on why their site says that. A big thanks to John Todd over at Indmar for tracking down a wiring diagram for me. So here is whew I am at.

My original alts all had the one orange (power) wire attached with nothing else. The alt is grounded through the block. However u do need the harness coming out of the back of the alt. A thanks to the tech up at Watersports Marine for hooking me up with the Napa part number of TSC200 for the harness. Now here is where it got confusing. While the alt is single wire capable for this upgrade you need to crimp both outputs of the harness to the purple ignition/excite wire for some reason. While I don't know exactly why this is, this is what Indmar calls for in the instructions for the 70 amp upgrade.

I am not sure if the original owner or the dealer did the upgrade. When they did the did upgrade the gauge of the power lead to the breaker and to the starter. I k ow this because that wire while mix looked new without grime or engine compartment residue like the others. However they forgot to wire up the harness. Also this wire was the correct gauge recommended.
Ran the boat for 2 hrs last nite. My alt kicks in immediately at the start now rather than having to rev it. It's showing 14.5 volts at the alt and at the batts when running. My batts are both showung 12.7 volts rest.

Hopefully this should cure the issues. I can't thank everyone enough for the heads up and the input. Electrical stuff is always something I just don't really get or know to much about. Learned a ton qbout it now tho. If anyone thinks I an missing anything let me know

mikeg205
10-12-2011, 03:46 PM
phew ...sounds like the alternator terror is over....

thatsmrmastercraft
10-12-2011, 03:48 PM
So made some progress on the situation. Took some calls to several dealerships as well as Indmar and skidim.

While the kit from ski dim says the harness is not needed it is needed so not sure on why their site says that. A big thanks to John Todd over at Indmar for tracking down a wiring diagram for me. So here is whew I am at.

My original alts all had the one orange (power) wire attached with nothing else. The alt is grounded through the block. However u do need the harness coming out of the back of the alt. A thanks to the tech up at Watersports Marine for hooking me up with the Napa part number of TSC200 for the harness. Now here is where it got confusing. While the alt is single wire capable for this upgrade you need to crimp both outputs of the harness to the purple ignition/excite wire for some reason. While I don't know exactly why this is, this is what Indmar calls for in the instructions for the 70 amp upgrade.

I am not sure if the original owner or the dealer did the upgrade. When they did the did upgrade the gauge of the power lead to the breaker and to the starter. I k ow this because that wire while mix looked new without grime or engine compartment residue like the others. However they forgot to wire up the harness. Also this wire was the correct gauge recommended.
Ran the boat for 2 hrs last nite. My alt kicks in immediately at the start now rather than having to rev it. It's showing 14.5 volts at the alt and at the batts when running. My batts are both showung 12.7 volts rest.

Hopefully this should cure the issues. I can't thank everyone enough for the heads up and the input. Electrical stuff is always something I just don't really get or know to much about. Learned a ton qbout it now tho. If anyone thinks I an missing anything let me know

Definitely had to clear a few hurdles to get the right info. The hazard, and eventually the feeling of satisfaction of a used boat.

gweaver
10-12-2011, 06:04 PM
I run single wire 90amp alternators in my other boats. They do not load up till rpm gets close to 2000.

For clarification- do you mean alternators don't start putting out (sufficient) current until they hit 2000 rpm? I'm trying to resolve an issue on my boat- took it out twice, both times never got it above idle. Second time the engine died (not sure why) and I wasn't able to restart- dead battery. Anyway, battery tests good, haven't been able to find a place that can check the alternator. I'm wondering if part of the reason it wouldn't restart is because I'd never gotten the engine above idle so it wasn't recharging the battery.

thoughts?

Thanks,
G

oldairboater
10-12-2011, 10:29 PM
The alternators on my airboats don't load up at idle ever. Once the boat gets above 1800 rpm they actually load up and start charging. Once they load up they stay up and continue to put out voltage even at idle till I turn off the boat. If I left that boat or the other just idling then the alternators would never load up. The batteries would die. I have to make sure to bring the rpm up at least once if I plan on leaving the boat at idle for a long time. For clarification- do you mean alternators don't start putting out (sufficient) current until they hit 2000 rpm? I'm trying to resolve an issue on my boat- took it out twice, both times never got it above idle. Second time the engine died (not sure why) and I wasn't able to restart- dead battery. Anyway, battery tests good, haven't been able to find a place that can check the alternator. I'm wondering if part of the reason it wouldn't restart is because I'd never gotten the engine above idle so it wasn't recharging the battery.

thoughts?

Thanks,
G

JimN
10-13-2011, 10:44 AM
For clarification- do you mean alternators don't start putting out (sufficient) current until they hit 2000 rpm? I'm trying to resolve an issue on my boat- took it out twice, both times never got it above idle. Second time the engine died (not sure why) and I wasn't able to restart- dead battery. Anyway, battery tests good, haven't been able to find a place that can check the alternator. I'm wondering if part of the reason it wouldn't restart is because I'd never gotten the engine above idle so it wasn't recharging the battery.

thoughts?

Thanks,
G

Alternators don't put out full voltage and current at idle. When an alternator is operating (generating voltage/current), it puts a load on the engine. As the load on the charging system increases, the load on the engine increases- there's no such thing as free energy. However, using a smaller alternator pulley can "trick" the alternator into operation at lower RPM or, if you want to allow the engine to see less load, you can use a larger pulley as long as you tend to run it at mid-high RPM more than at idle.

If you have a NAPA store or automotive electrical repair shop nearby, they should be able to check your alternator.

Why haven't you ever gotten the engine above idle?

gweaver
10-13-2011, 11:02 AM
Jim- so far I'm 0 for 2 with the boat. I'll admit, this is my first boat, so I'm learning as I go. First time I took it out, the transmission started slipping right around 1500 rpm- low fluid, apparently. I was never able to get above about 10 mph, so I turned around and went back to the ramp. Second time I tried (after filling transmission), we got about a mile down river (I was about 200 yards from getting out of the no-wake zone) and the engine died. Not sure why, unless it was because battery voltage dropped too low. Wasn't able to re-start it. Got towed back to the boat ramp.
I've had the boat running off the garden hose, but I've just let it idle for the most part.
I took the alternator in to Autozone and O'Reilly- Autozone couldn't test since it was a 1-wire alt and O'Reilly couldn't find an automotive cross-reference to use with their computer diagnostic machine. Will try NAPA this weekend.
G

JimN
10-13-2011, 11:12 AM
Jim- so far I'm 0 for 2 with the boat. I'll admit, this is my first boat, so I'm learning as I go. First time I took it out, the transmission started slipping right around 1500 rpm- low fluid, apparently. I was never able to get above about 10 mph, so I turned around and went back to the ramp. Second time I tried (after filling transmission), we got about a mile down river (I was about 200 yards from getting out of the no-wake zone) and the engine died. Not sure why, unless it was because battery voltage dropped too low. Wasn't able to re-start it. Got towed back to the boat ramp.
I've had the boat running off the garden hose, but I've just let it idle for the most part.
I took the alternator in to Autozone and O'Reilly- Autozone couldn't test since it was a 1-wire alt and O'Reilly couldn't find an automotive cross-reference to use with their computer diagnostic machine. Will try NAPA this weekend.
G

Your alternator should have been able to keep up at 1500 RPM and a mile long trip shouldn't have discharged your battery.

Here's a brief explanation of your electrical system.

Your battery is there to crank the starter. Your alternator is there to re-charge the battery after cranking and to supply current for the accessories and ignition system. If your battery wouldn't crank the engine after a mile, you have: a dead battery, excessive current draw, high resistance on the battery cables or loose/dirty connections.

If you have cranked your engine to the point that it wouldn't turn over at all, you probably have cooked your starter. If you killed your battery to the point of being stone dead and then ran the engine by jump-starting it, you may have cooked your alternator- it's not made for this, it's only able to provide about 55A-90A. Your starter draws between 150A and 350A when cranking, depending on compression, etc.

You have a car engine in your boat. Call around- you're in California! That's where the Car Culture started and you shouldn't have any problem finding a place that can check a starter, battery or alternator.

gweaver
10-13-2011, 12:53 PM
After the second outing, I charged the battery and tried to start the boat. Started up fine, idled for several minutes in the driveway. I took the battery to be tested and they say it's a good battery. I'll work on getting the alternator checked.

G

thatsmrmastercraft
10-13-2011, 12:59 PM
After the second outing, I charged the battery and tried to start the boat. Started up fine, idled for several minutes in the driveway. I took the battery to be tested and they say it's a good battery. I'll work on getting the alternator checked.

G

Get a voltmeter on the battery while the engine is running and see what kind of voltage you are seeing.

mikeg205
10-13-2011, 03:00 PM
Whenever I change belts...always have the alternator bench tested...free at autozone...free excuse to go out...

gweaver
10-14-2011, 01:01 AM
Autozone claims they can't test it as it's a one-wire unit and they can't cross-reference with any car alternator. Apparently in their fancy test rig, there's a 3-prong plug that's supposed to attach to the alternator so they can get their readings. No place to plug it in. I'll have to go the voltmeter route.
G

CantRepeat
10-14-2011, 07:04 AM
Autozone claims they can't test it as it's a one-wire unit and they can't cross-reference with any car alternator. Apparently in their fancy test rig, there's a 3-prong plug that's supposed to attach to the alternator so they can get their readings. No place to plug it in. I'll have to go the voltmeter route.
G

I'd try a NAPA store for the test.

Jeff d
10-18-2011, 02:03 PM
While the alt is single wire capable for this upgrade you need to crimp both outputs of the harness to the purple ignition/excite wire for some reason. While I don't know exactly why this is, this is what Indmar calls for in the instructions for the 70 amp upgrade.

Typically you'd loop the constant + lead back to the charging post. Then connect the excite wire to the purple ignition lead. The other small gauge black wire on the factory harness is a ground IIRC and should be taped off and left unused. Connecting both the excite and the "constant" + leads to the purple wire will likely work just as well though.

Basically all "3 Wire" alternators are not the same. The OEM alternator on the LTR was a 51 amp Prestolite style with the external regulator that are 3 wire. The 3 wires on these consist of 2 light gauge wires (1 for regulator ground and another for ignition switched +) then one heavy gauge for charging. For whatever reason there's a dedicated ground for the regulator rather than it just picking up ground from the chassis attachment points.

The internally regulated 10si/7si styles have 2 small gauge (1 for constant + and 1 for ignition switched +) and then the same heavier gauge wire for charging. There's no ground "wire" these just pickup ground from the mounting points.

There may be other "3 Wire" styles but these are the two I've had experience with.

curtish
10-19-2011, 12:51 AM
:popcorn:......