Mastercraft Alternator Swap

I just installed a new system and apparently it was too much for my alternator. Now it is time for a new one and I was hoping to get some reccomendations on what alternator size I need, and how hard it is to install on a 99' Maristar.
THANKS!

Putting a new alternator in voids your warranty on the engine. But if you are going to do it, get the 90amp alternator that is standard on some of the bigger engines that are options on MCs

Good Luck

What Barefooter said is correct!!

double posted alt is your ticket.

I think those are Leece-Neville marine alternators. You can get a good deal on them from from Pearland Alternator. http://www.palcoelectric.com/

I just gave them the model number off of the one I had and asked what I could substitute in that had more amps.

I had to change a connector on 1 of the small wires, but I was done with the swap in about 5 minutes.

I bought my 135 marine amp for my prostar about a month ago from a guy in Dallas, only $109 plus shipping on ebay.

Adam-I have an '01 SAN and called that guy in Texas and he did not have one that would swap(something about the fuel pump). I called West Coast Correct Craft and they hooked me up with a 100 amp alt and upgraded wiring harness for $300. They said it would not void my warranty because it was from Correct Craft. I wish it was a little bigger, but they said it was going to be easier on the belt and bearings. The alt I'm replacing is a 55amp Mando(I believe).

thanks to all who have helped. Is anyone faimiliar with how to remove the belt in order to swap the alternator? Any other tips/time savers? THANKS

I took the alternator out of Jasons 209 last night it came out in 5 min no problems, Whats this crap about Voiding the warranty on the motor if you install a upgraded alternator? I hope thats not true. If it is true thats another reason to buy a CC LOL.

Going over 55mph is illegal in some states too...

Keep the old alt. put it back in if there is every any engine failure.

Make sure it is a marine alternator.

Non marine alternators are cheaper to buy, but if your boat explodes in a big ball of flames because the non-marine alternator ignited some gas fumes then it will end up costing you a LOT more.

Aftermarket alternators does not void your warranty on Indmar Engines. I called Indmar when I upgraded my alternator to a 150 amp alt. to get the correct pulley size. I talked to them about me going to a bigger aftermarket alternator and they had no problem with it and assured me that it does NOT void the warranty.

IMO if you ask enough people on this subjuct sooner or later someone's gonna say "VOID WARRANTY" for some reason or another. I didnt realy think MC would void a warranty on a motor for a aftermarket alternator but stranger things have happend. My advice is if you ever have a electrical problem and you need the dealer's help put the stock alternator back on and bring it to the dealer, and tell them Rod McInnis work on your alternator and now it dosent work. LOL

J/K Rods the man when it comes to Alternators,

Anything over 100amps going through the computer WILL VOID WARRANTY on MC,CC or malibu's.They will also know if there was another alternator there because computer is gonna burn out and the boat will shut down or worse catch fire.
IMO you will be OK either way unless you change the pulley's so dramatically that it gives you super high output in low rpm simply because the high output alternator doesn't give you very much juice in low rmp.hope that makes sense.I just delt with it the last month or so.I went with 2 separate alts that are not high output alt.but gives alot of juice in low rpm's.Also went with a smart switch,also 3 blue tops for power storage.

Big Ed-thats exactly what correct craft told me. That's why I opted for the 100amp and 3 blue tops. Also, on a side note, be careful hooking up those solenoid islolaters...the guy that owned the boat before me hooked up my isloater in a way that fried the breaker box(brain), which cost me $800 to fix. Since then I have replace the solenoid with a simple 3 way Perko, as they recommended.

I'm getting the charging system and the switch installed by the MC dealer or their mastermind that they believe in so everything is under warranty!
Thanks for looking out!

Hey Big Ed: Did you believe it when your mom told you that you would get worms if you eat cookey dough? IMO who ever told you that is full of it. They just dont want you creating extra work for them if things go wrong with a over charging situation.

Run the system completley seprate of your computer and this is a non-issue,

Dealers are just trying to protect there ass. I would do the same thing if I was a dealer or boat manafactuer. Some people cut corners on installs and then make the dealer or manafactuer pay for there mistakes. this is there way to protect them self's and can you blame them.

Big gamble with a $20,000-$25,000 engine Grant. You give a lot of good advice on these boards, but you are kind of sticking your neck out on this one. If you are wrong it could have some bad results. If it was ok to put bigger alternators on these engines it would be an option.

More like $6k, don't worry Grant knows these better then most dealers.

Grant ~ Yes definetly got to run the system separate from the computer and it becomes a non-issue but I would like to charge my batteries while I'm wakeboarding and that would be the only way...and still be under warranty,but I hear exactly what you are saying.

As far as getting worms from eating cookie dough...I thing I have a worm problem.LOL

A Mastercraft engine replacement is not $6K...

For me yes $6k, for you $20k+...

You don't replace the whole engine unless you are a fool.

Why do I even bother debating these young MC guys???

Mike you are correct, an MC replacement engine is about 6K, if you can rebuild it, it is about 4K

Mike It may be $6k for the Engine Replacement, but we are talking about the Computer and all the electronics that could get fried from the aftermarket Alternator. I have asked 3 different Mastercraft Dealers and they all said the same thing, if you want a higher output alternator then get the upgraded one from Mastercraft. My dealer told me that they would give me credit for the old one on my boat since it is still basicly new, and then discount the higher output OEM one. Not sure if you have ever looked into what all the electrical would cost but I can bet that you get a lot closer to the $15000K mark then the $6k to put the new engine in.

Barefooter your right.I am sticking my neck out. I would hate for someone to install a HO alternator and somthing go wrong, So I am officialy retracting all advice for installing any aftermarket goodies that could void your waranty what so ever. My new mantra is "Leave it Stock and let it rock".

So Mikeski for the record I am 34. Not sure if that makes me a young MC guy. You are correct in saying only a fool would replace the whole engine (although I don't appreciate the shot.) If you read my original post it said nothing about "replacing" the engine only making reference to the cost of the engine. You usually have some good things to say up here so I am a bit surprised by the unnecessary comment you made towards me. My post was with good intention and was taking by Grant as I meant it.

Does anybody know the specs or part number for the upgraded MC altenator? I keep asking my dealer about it and they said there is no upgrade. Mine isn't under warrenty so I am not going to worry about putting in an MC altenator. I also had them run up a quotes on a few engine replacements for kicks. A short block replacement~$4000 Long block ~$5000 Crate engine from Indmar with all electronics~$6500 He said the other two are so high because you basicly have to tear the engine down and rebuild it back up. The crate engine you just unpack and hook it up. Anyway you look at it, it's a lot of money.

anyone ever hear of an electrical failure frying pistons, rods, crank, cams, etc?????? Now as far as an alternator goes electrical devices draw whatever current they require to operate, not the alternator forcing 100 amps thru everything in the system or all your lights would burn out everytime you start your engine not to mention everything else that only takes 2-5 amps like blowers, gauges, pumps, etc.
Hell your stock alternator puts out 55-65 amps on most chevy based engines and doesnt fry everything in sight, ever wonder why, cause it puts out 13.8 +- to everything and the load (demand on it) determines how much current it will put out at any one time.

Well said bob.

To elaborate on what Bob and Grant have said here, I'll offer my own experience.

For many years we owned a 30Ft Class A motorhome, 454 CID F.I. engine. The engine came with the typical 65 amp large case Delcotron alternator. I had a total of 5 Optimas on board, 1 for the house lights, three for the stereo, and one for the chassis. By manipulating the Perko switches and emergency start solenoids, I could do just about any batt. combo necessary to get the engine fired.
The 6500 watt on-board generator was coupled to a 15 amp charger-inverter, and charged all five batteries via a 15 amp charger built into the house inverter/fuse panel. there was also a 100 watt solar panel on the roof, self-regulating. The most I ever saw it produce was 12amps at 13.1 volts. The solar panel shut down when either the engine or generator was running. High-$ Siemens Unit.

Over the course of 5 years or so, I went through a total of 4 factory-fresh alternators. Two of them failed at the brushes, two of them failed in the internal regulator. One stuck on high-charge, one stuck on low charge. The one that stuck on low charge allowed me to limp 500 miles home across Nevada from Delta Utah. I did so by periodically cranking up the generator, and charging the batts with it. The one that stuck on high charge casued the belt to squeal, and necessitated a roadside swap.

I got tired of swapping out factory alternators finally, standing on your head in a class A coach and working on something by feel is not fun.
I bought an aftermarket R.V. specific h.o. alternator that put out 80 amps at idle @ 13.8 volts, and 155 amps @ at 2800 RPM.It was balanced, internally regulated, and was about $450.00. Built by Leece-Neville, if memory serves. The alternator gurus I dealt with told me to use the generator as much as possible to charge the batts, and to plug the coach in at home before going on a trip to get the batts up to max charge, even after letting the solar panel do it's thing for a week or so before leaving. Even the best alternator has a limited amount of life in it, and that limit is defined by how hard you push it and how long you push it. Obviously, 5 Optimas was too much for the stocker.

None of my alternator failures caused any problems beyond their own case, unless you count a fried belt.
For an high-output alternator to cause the failure of ECM or other engine-managment systems would be highly unusual, IMHO.
I know of no ECM's that have the alternator's voltage regulation circuitry built into them, if that was the case every time you had an alternator failure you would be changing the ECM as well. It makes sense that the engineers would isolate the charging system from the ECM and engine management programs for that very reason. To the best of my knowledge, the ECM monitors voltage output, but does not control it.It will throw a trouble code if output is too high or too low, but that is it.
So, Mastercraft and the other boat manufacturers are probably looking at this with the broad brush that their legal dept.s' tell them works.

1) Change anything, warranty void.
2) Have anybody but a factory tech change anything, warranty void. (And less $ in their pockets, too)

The builders cannot afford to assume that intelligent people are going to make changes to the product.
They must assume that the same people who need the "Do not use underwater" stickers on their blowdryers are buying boats. In many cases, judging from what I have seen at the ramp over the last 20 years or so, they are right.

This goes back to the basics of hot-rodding, guys. The boat is a system, a package, a group of systems operating together.
If you increase the H.P., increase the strength of the trans, and improve the brakes.

If you add a H.O. Alternator, make sure the wiring and breaker systems are capable of handling the increased heat, voltage, amperage, etc. If you are worrined about the warranty, and that concern exceeds your desire to improve your sound system and support that improvement with a high output alternator, then don't mess with it.


Like Bob said, I cannot envision a case where that 10 gauge wire that runs from the alternator through a breaker to the starter supply lead is going to cook the main bearings, break a camshaft,etc.. or the fry the ECM for that matter. Not if it is installed correctly and the associated systems are upgraded with it..

Just another opinion from an old guy...

(Message edited by sam8 on April 12, 2005)