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Does my 94 seadoo have an alternator?
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Dr Honda
Well-Known Member
OK... you are asking 2 different questions... so....
1) Yes... it has an alternator.
2) Anything built in 94 has a magneto, and CDI ignition, so battery voltage is irrelevant once it's started. BUT... depending on what model it is... the speed limiter, or MPEM may kill the engine if the battery wires are disconnected, just because you have an open circuit.
So... the real question is.... Why do you ask? Obviously, you are trying something, but you have asked about whatever problem you are having.
1) Yes... it has an alternator.
2) Anything built in 94 has a magneto, and CDI ignition, so battery voltage is irrelevant once it's started. BUT... depending on what model it is... the speed limiter, or MPEM may kill the engine if the battery wires are disconnected, just because you have an open circuit.
So... the real question is.... Why do you ask? Obviously, you are trying something, but you have asked about whatever problem you are having.
Thanks for the reply. It is a 94 Seadoo XP Rotax Powered
I just bought the seadoo and took it out the first time last weekend, cranked it up and rode about 200 yards and stopped to swim. When I tried to restart it would not crank. When holding the starter button down, it would only turn 3-4 times and then only half turns after that.
Had the battery tested and they said it was a good battery but low, so I charged it up and it cranked right up. Guys I work with told me to disconnect the battery while running and if it quits then the alternator is bad.
So my questions are: Do I have a problem because it quits when the battery is disconnected and If so how do I correct it?
I'm not very mechanically inclined so I don't know what a mpem is.
I just bought the seadoo and took it out the first time last weekend, cranked it up and rode about 200 yards and stopped to swim. When I tried to restart it would not crank. When holding the starter button down, it would only turn 3-4 times and then only half turns after that.
Had the battery tested and they said it was a good battery but low, so I charged it up and it cranked right up. Guys I work with told me to disconnect the battery while running and if it quits then the alternator is bad.
So my questions are: Do I have a problem because it quits when the battery is disconnected and If so how do I correct it?
I'm not very mechanically inclined so I don't know what a mpem is.
purple_people_eater
New Member
ok first of all the is no technical alternator on a jet ski. that test is obsolete even on cars and truck with efi systems, it only works on carbed and some port injected vehicles if you go do that to your car in your driveway it will die also even if the alt is working because now days the computer draws its current directly from the battery and the alt. simply keeps the battery maintained. an alt is basicly a magnet spinning really fast inside of many coiled lines of copper, thus the magnetic force creates AC energy then is processed by a voltage regulater and converted to 12 volt DC.
in the case of your doo there is want is called a magneto that spins inside coils of copper wire and produses power much like an alt. most likely your voltage reg. has went out. to test this get a voltmeter and turn it to its 12v DC setting. start your ski and put the meter on the battery posts, then rev your ski a little bit. it should move over 12.4v if not then your voltage reg is probably gone. i'm not sure if that model has a charging fuse but that could be it too. if not the fuse then its nost likely the reg, which i don't know whether or not its built in to the mpem on that model. if it is there is a exturnal replacement kit you can google.
in the case of your doo there is want is called a magneto that spins inside coils of copper wire and produses power much like an alt. most likely your voltage reg. has went out. to test this get a voltmeter and turn it to its 12v DC setting. start your ski and put the meter on the battery posts, then rev your ski a little bit. it should move over 12.4v if not then your voltage reg is probably gone. i'm not sure if that model has a charging fuse but that could be it too. if not the fuse then its nost likely the reg, which i don't know whether or not its built in to the mpem on that model. if it is there is a exturnal replacement kit you can google.
So you are saying that there is not a problem just because the seadoo cuts off when the battery is disconnected. If that is the case then I may have no problem at all.
--or--
Are you saying I definitely have a problem because the seadoo should not cut off with the battery disconnected and the problem could be any of the following: magneto, cdi ignition, speed limiter, mpem, voltage reg., or charging fuse.
I am now more confused than when I started. Any help would be appreciated.
--or--
Are you saying I definitely have a problem because the seadoo should not cut off with the battery disconnected and the problem could be any of the following: magneto, cdi ignition, speed limiter, mpem, voltage reg., or charging fuse.
I am now more confused than when I started. Any help would be appreciated.
I really think its your rectifier...start the machine and put a voltmeter on the battery. Rev it to about 5000. The voltage should stay close to the same. If it spikes up to 14-15 volts, that is your issue and you need a replacement. Its a fairly common issue, not as much so on the smaller motors.
It is not. The magneto is the old version of what a stator is now. the Stator creates the power, and the rectifier turns it into good DC? 12volt power.
Its in the grey ebox; just a matter of getting it out, opening it up, and replacing it.
But before all that you need to do the voltmeter test.
But before all that you need to do the voltmeter test.
Dr Honda
Well-Known Member
Hi,
1) As above... you can't disconnect the battery. That's a old test, and it really doesn't tell you anything.
2) Your battery is probably going bad. If you are going to keep the ski, buy a new one. A weak battery is hard on the starter, and hard on the charging system.
3) To test the system, use a volt meter, and just hook it to the top of the battery. Start the engine, and bring it up to 5000 RPM. You should have 13.5 to 14.5v. If you don't, then there is a good chance that the regulator/rectifier unit has gone bad. It is in the gray electrical box. It is square shaped, and has 4 wires coming out of it. On a seadoo, it is very rare that anything else goes wrong with the charging system. I guess I should add... Don't overheat your engine if you do this out of the water. You can only run the engine dry for about 15 seconds.
With that all said... please don't get confused. The original question of the "Alternator" is just semantics. By the purest terms... yes, you have an alternator. In the magneto housing of the engine, there are power coils, that produce alternating current. (on the yellow wires) From there, the "Rectifier" changes that to "Direct Current" (DC) voltage... and the "Regulator" keeps the voltage at a usable level. (around 13.5 volts) As I already said... your Regulator, and Rectifier are in a single unit. The word "Magneto" will get used with a charging system on watercraft, and motorcycles, because many of them don't have an external alternator. In the purest terms, a "Magneto" is an unregulated power source. The reason a SeaDoo has a "MAG" is because the ignition is a magneto/CDI system. (for most of the engines) The Mag coil puts out an unregulated voltage, and can reach 300v. The high voltage is needed to charge the capacitor in the CDI ignition.
Sorry that got long... but I wanted to give you the EXACT info, that may have been confusing you.
Anyway... check the output with a volt meter, and let us know what you get. But, it really sounds like you need a new battery. (that may be the only problem)
1) As above... you can't disconnect the battery. That's a old test, and it really doesn't tell you anything.
2) Your battery is probably going bad. If you are going to keep the ski, buy a new one. A weak battery is hard on the starter, and hard on the charging system.
3) To test the system, use a volt meter, and just hook it to the top of the battery. Start the engine, and bring it up to 5000 RPM. You should have 13.5 to 14.5v. If you don't, then there is a good chance that the regulator/rectifier unit has gone bad. It is in the gray electrical box. It is square shaped, and has 4 wires coming out of it. On a seadoo, it is very rare that anything else goes wrong with the charging system. I guess I should add... Don't overheat your engine if you do this out of the water. You can only run the engine dry for about 15 seconds.
With that all said... please don't get confused. The original question of the "Alternator" is just semantics. By the purest terms... yes, you have an alternator. In the magneto housing of the engine, there are power coils, that produce alternating current. (on the yellow wires) From there, the "Rectifier" changes that to "Direct Current" (DC) voltage... and the "Regulator" keeps the voltage at a usable level. (around 13.5 volts) As I already said... your Regulator, and Rectifier are in a single unit. The word "Magneto" will get used with a charging system on watercraft, and motorcycles, because many of them don't have an external alternator. In the purest terms, a "Magneto" is an unregulated power source. The reason a SeaDoo has a "MAG" is because the ignition is a magneto/CDI system. (for most of the engines) The Mag coil puts out an unregulated voltage, and can reach 300v. The high voltage is needed to charge the capacitor in the CDI ignition.
Sorry that got long... but I wanted to give you the EXACT info, that may have been confusing you.
Anyway... check the output with a volt meter, and let us know what you get. But, it really sounds like you need a new battery. (that may be the only problem)
Running it for 30 sec out of the water is fine. If you have to do it multiple times let it sit for 5 to 10 mins.
results of the voltmeter test:
12.5 with engine off
12.75 at idle
13.75 at 5000rpm (I held at 5000 for about 5-10 seconds) don't know if I should have
14.1 at 5500-6000rpm (same thing)
Now I do have to point out I have been told three different things in this thread as to what these #'s mean:
purple_people_eater - "it should move over 12.4v if not then your voltage reg is probably gone"
Minnetonka4me - "Rev it to about 5000. The voltage should stay close to the same. If it spikes up to 14-15 volts, that is your issue and you need a replacement"
Dr Honda - "Start the engine, and bring it up to 5000 RPM. You should have 13.5 to 14.5v. If you don't, then there is a good chance that the regulator/rectifier unit has gone bad.
A couple of other unrelated things I noticed and would like help with: The engine is running a little rough. (I don't know what normal would be so I don't have anything to compare it to). A large amount of smoke from the back of the ski. About a puddle of water discharged from underneath and to the rear of the ski. (there was a small amount of oil mixed in)
Thanks
12.5 with engine off
12.75 at idle
13.75 at 5000rpm (I held at 5000 for about 5-10 seconds) don't know if I should have
14.1 at 5500-6000rpm (same thing)
Now I do have to point out I have been told three different things in this thread as to what these #'s mean:
purple_people_eater - "it should move over 12.4v if not then your voltage reg is probably gone"
Minnetonka4me - "Rev it to about 5000. The voltage should stay close to the same. If it spikes up to 14-15 volts, that is your issue and you need a replacement"
Dr Honda - "Start the engine, and bring it up to 5000 RPM. You should have 13.5 to 14.5v. If you don't, then there is a good chance that the regulator/rectifier unit has gone bad.
A couple of other unrelated things I noticed and would like help with: The engine is running a little rough. (I don't know what normal would be so I don't have anything to compare it to). A large amount of smoke from the back of the ski. About a puddle of water discharged from underneath and to the rear of the ski. (there was a small amount of oil mixed in)
Thanks
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