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Discussion Starter #1
Hello,
I am hoping some of you could lend me a hand figuring out why my son's JS550 won't charge the battery. Starts and runs fine until the battery voltage drops to low. I have checked the coil resistance as per the manual and those readings compare to the specs. I also have checked the AC voltage coming out of the coils with the engine running as per the manual. The highest value I could measure was 1 volt AC while reving the engine. The Manual suggests this may be due to the magnets in the flywheel becoming weaker and I just wanted to run this by you guys for a second oppinion before I start looking for another flywheel... If I am missing something on checking this out please let me know.
Thanks in advance,
J
 

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I doubt that the flywheel magnets have weakened to the point that it will not charge. I think you have a broken wire at the stater coil. It prob touches enough to pass resistance checks but becomes detached while running. Thats my guess!
 

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There are two coils behind the flywheel. One supplies the timing\voltage for the spark, and the other supplies the voltage to charge the battery.

You say it runs until the voltage gets too low -

It should run all day, even with a dead battery. the starter would quit, but the battery is not used for "running" the engine. The battery is only used for the starter.

The above statements apply to a stock configuration.

There is an aftermarket flywheel system known as a "total loss" system.

It doesn't charge the battery at all. The advantage of this is a much lighter flywheel, which gives increased performance.

So if you are sure you have the stock system, then it is probably the coil under the flywheel.

It could also be the voltage regulator. That is a small metal box inside the electrical box. It is in charge of regulating the voltage to the battery.

One thing I recommend to everyone who has these old JS skis, is to run nice thick ground straps between the engine and the electrical box, and from the electrical box to the neg terminal on the battery.

These skis were built using a tiny wire to provide ground for the system. I had a lot of electrical issues until I did this. I haven't lost a component since!

OL JS Rider is correct about a coil sometimes passing a resistance test but failing under operation.
 

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Discussion Starter #5
Yea, it would run for a couple of days during our camping trip this summer until the battery was too weak to start it. That was probably due to the starter motor pulling the battery down not the ignition, I understand that now thanks.

I ohmmed out the charge coils at the eBox as suggested:
Gr - Gr = 2.1 ohm
Gr - Blk = 1.2 ohm and on the other G - Blk it would read 2.2 ohm ( would think those readings should be closer to the same?)

I agree 100% that an ohm test is not the same as a live circuit under load. think I will pull the cover off the flywheel and inspect the connections down there. Tell ya what I find when I get the chance.

Thanks for the input!
 

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Discussion Starter #6
So I had some time tonight to dig a little deeper into my charging system problem. When I removed the flywheel cover it was pretty obvious the o-ring had been damaged previously. It's been letting moisture inside for quite some time now...

I also noticed the charging coil windings were loose around the core. My ohmmeter readings would jump all over the place when I wiggled the coil windings. I also found one wire on the windings were just hanging on by a thread (literally!) to the ground terminal, looks like the solder joint failed.

Any one have a good used charging coil they would be willing to sell to me?

Besides obviously cleaning up everything, is there anything else I should take care of while I have the front cover off?

Thanks for the replies, I have really appreciated your help on this one.
 

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I would hit ebay there are a couple on there. look under ebay motors, parts and acess., personal watercraft, kawasaki jet ski 550. beware! you will be here alot! It is addicting.
 

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Discussion Starter #9
Thanks, I found a WSM charge coil for like $30 at DennisKirk's site. Got it installed today and I have CHARGING now!
 

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ok I need a little help

I know I am posting on an old thread but I am having a similar issue.
except my ski is acting like it IS running off of the battery.

I just bought a 88 JS550. Never owned one before and this past weekend I taught myself how to stand up on one... yay me. but I sure did not have it easy. I charged the battery because it was dead when I got the ski. The batt held a charge in my garage for 3 days so I figured im good to go.
I launch it in the lake and fell off about 20 times... every time I fall off the motor dies (carb was set poorly)
finally get sick of it cutting out so I go to shore and adjust the carb.
I go to do a off shore take off and 10 feet later the ski acts like it has no power and sputters to a stop. The batt is now dead and cant turn over the motor at the speed needed to start. I grab my booster pack and it fires up but when I try to take off it dies again in 10 feet.

I hook up the booster pack and have a smoke then start it... then apparently the 10 min I took to have a smoke while the booster pack charged up the batt was enough for me to get 100 yards out of the ski before sputtering to a stop


then I pull the battery and charge it over night. this morning I put it back in the ski and I rode it on the lake for about 20 min with the ski acting flawlessly. I let go of the throttle and it idles... I hit the throttle and it revs up and takes off like a bat out of hell... but after 20 min of constant running the damn thing just sputterd to a stop on me again.

it has plenty of fuel
the carb is set right.
the batt wont supply enough juice to turn over the motor (yes I know the first 2 have nothing to do with the batt)


my issue here is if the ski cant run off the batt even if it needed to...... then how is it that im running my batt down running my ski?

and with my volt meter im getting 12.5 volts off the batt when running and that number was lower and lower every time I checked it until it quit only giving 11.3 volts when it shut down the last time.


everything on my ski appears stock....

I am just bugging out looking at a $300 stator assy for a $500 ski



shoot me a few ideas ANYONE before I swill enough :D beers :D to dump waaay to much money in a ski that prolly aint worth what I am thinking of doing.


WrecK
 

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Discussion Starter #12
Yup, it sounds like you need a new charge coil. The voltage readings you are seeing indicates there is no charge when the engine is running. I found just a charge coil online with a little research and it only cost around 30 clams if I remember correctly. No need to spend the dough on both coils if you engine will still run, just need to swap out the one that is dead.

With your battery being so deeply discharged on a lot of occasions it is likely that it has become sulfated, so you might want to budget for another one.

If you don't have a repair manual for your ski yet, I would strongly suggest you get one! It helped me a ton when trouble shooting this problem as well as everything else that I have managed to teach myself about fixing this toy :laugh:

When I got the front cover off I discovered the o-ring seal was damaged, letting water in. When I got the flywheel and the coils removed I discovered the front crank seal had failed... so be prepared to find more problems, just saying!
 

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yaaaaay

Thanks for the reply...

The thing I dont get is the one guy said that the ski can run all day long with a dead batt, However... when my ski runs it drains the batt untill the batt is dead.

I just dont understand how with the 2 coils (one for charging the batt and another for providing spark) how my batt can run down while running my ski.


anyway... is there a possability that the voltage regulator in the elec box can be bad?

I have not tore down my ski yet but if anyone knows what wire I need to find to test from the coil going to the voltage regulator to make sure that power is even being sent to the regulator.. that would be helpfull.





I have rebuilt the motor in my truck... in my Harley, and in my lawn mower... but this ski is a totaly different animal....lol
 

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Discussion Starter #14
You can ride your ski all day long when you are fresh and rested, sort of like being brand new.

When you are tired and wore out you can't ride as long before getting weak, sort of like your battery is I think :)
 

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I got it fugured out... almost

I looked at the wiring harness going from the stator (coils / magneto) and I found that the black wire (ground wire) was melted and totaly roasted. it was also completely GONE in the E-box. I did however figure out where it went in the E-box and I pulled the female pin terminal from the E-box end of the plug and created a new ground wire for the E-box internally. Then I ordered a new wiring harness to go from the E-box to the stator assy.

then once I took the stator cover off and removed the flywheel I found that the charging coil was jacked and the exciting coil under the pulsing coil was starting to fall apart as well (intermitent issue) and must have been the cause of the ski just shutting down.

yes this means that the batt was only going dead due to restarting the ski over and over again

now when I removed the wire retainer off of the stator plate (the plate the coils are mounted to) the wires shifted and most of them just fell out of there connectors.


here is my dilema.

I have the charging coil monted to the plate
I have the exciting and pulsing coil mounted to the plate
I have the brand new wiring harness set up and ready to go

I just have NO IDEA what wires from the coils get attached to the wires for the wiring harness
AND
which wire on the pulsing coil gets attached to the exciting coil


correct me if I am wrong


the red wire on the pulsing coil (the smallest coil) gets attached to the red wire on the wiring harness

the grey wire on the pulsing coil gets attached to the grey wire on the wiring harness and the two grey wires get attached to the loop coming out of the back of the exciting coil

the black wire on the wiring harness with the loop on it gets attached to the stator plate using the same screw that holds the wire retainer (the metal retainer that all of the wires get run through on the inside of the stator assy)

the 2 wires on the charging coil (on this coil they are yellow) get attached to the two green wires on the wiring harness (also assuming that it makes no differance which wire from the charging coil gets attached to either of the green wires


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I could really use a picture that shows good detail of someones stator assy and would allow me to see which wires are attached to what wires from the harness.

or if it is possible to see a scan of the diagram showing this in detail from a service manual if it shows it there?


thanks in advance.... once this is done I will be back on the water falling off every 100 yards or so.


seriously.. it sux owning one of these and not being able to take it out on the lake.
 

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Discussion Starter #16
If you don't have a repair manual for your ski yet, I would strongly suggest you get one! It helped me a ton when trouble shooting this problem as well as everything else that I have managed to teach myself about fixing this toy ;)
These are like 35 clams and will really speed up your learning curve, plus reduce the new owner frustrations, trust me.
 

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i hear ya....but

if I could see a pic or a scanned page in the book explaining what I need to know here then I get to save that 35 bucks and boom.. im out on the water.

I will eventually get the manual. Just, its sunday and I would like to get out on the ski today


any chance you see that page in your manual?
 

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Sorry to be off the topic a bit but I have a is 440 with a 550 black engine in (piston port) like yours. Do you know the year of your engine as I don't know the year of mine and I need to order a charge coil but need a idea of what year to look around. Cheers Nigel
 
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