SLX780 Stator

[Dodgeforce]

If the yellow stator wire comes off the terminal board, can this cause the ignition side of the stator to fail? Using a couple of day ago, and just dropped revs. Won't rev up and just bogs. Have had this before, opened the electrical box and first thing I saw was the yellow wire off. Made no difference refitting. Test and found red/white to blue red down to 38ohms, spec is 90. Yellow to red/purple was 1.4ohms, spec is 0.6. Hasn't been on for long, maybe a couple of hours, but over a year old.
So, I am looking for advice/opinions. This stator is an aftermarket, reading here OEM is the way to go. Are they a lot better than aftermarket, being so old? I am also thinking of getting it rewound, anyone used Ricks Motorsport Electrics? They have the stator listed on their site. Anyone else who can do them, or other suggestions?
cheers

[xlint89]

Not exactly sure what would happen if the yellow wire comes off the board? Nothing good I'm willing to bet.

The aftermarket elec parts have been hit or miss for most people that have tried them. They don't refund $$ on elec parts, so it's best to just get an OEM when you can. We KNOW they work. (as long as it tests within spec)

Looking over Rick's site, doesn't show Polaris PWC. If he does all those other power sports, I'm sure he can redo a Polaris PWC. The question would be how much if they do?

Before you start throwing $$ at it, have you checked the compression? Are you sure you're getting good fuel flow?

[Dodgeforce]

Yes compression and fuel flow are good. Just rebuilt the motor and crank after a leaning out problem Done the carbs and fuel pump, also modified the suction line to 5/16, as I wasn't happy with fuel pressure after rebuilding the pump. Tended to fluctuate at higher rpm, although steady at 2psi at idle. With 5/16, made a new pick up for the tank as well, steady at 5psi. Still breaking in when the problem happened, was going very well too...
Maybe OEM then, couple on EBay, just adds up when you convert to New Zealand dollar and add freight, so really want to make the right decision..

[xlint89]

Sorry for the late reply.

So you did a complete engine rebuild. Did you do a leak down test after reassembly? You really should in order to make sure there are no air leaks. Compression can be fine, but if sucking air and running lean, you'll have piston failure again.

Interesting about the fuel pump acting erratic after rebuild. Did you use a genuine Mikuni rebuild kit? I'm not convinced some of the aftermarket internal parts are as good.

Also weird the 5/16 fuel supply hose seemed to smooth the fuel pressure out. Were the old 1/4" hoses and clamps in good condition? Almost sounds like they may have been sucking air. How did you adapt the 5/16" hose to fit tightly on the 1/4" barb fitting of the fuel pump?

While we're on the subject. Have you addressed the aging fuel shut off valve? Might not be a bad idea to replace that with a newer one due to age and rubber internal parts. A Sea Doo replaceent valve is rather inexpensive and can save you some hassle down the line. The only down side to the SD valve is the location of the ON and OFF will differ from the factory locations.

Can you please post a few pics of your fuel system? I'm always curious to see what people are working with. Thank you

[Dodgeforce]

Yes, vacuum and pressure tested the engine after rebuild, held steady for over 10 mins. I used genuine Mikuni kits for the carbs and pump. The suction line on the fuel pump has a 5/16 fuel barb. Presume this is correct from Polaris? I thought it was as the same colour as the engine...

When I first put it in the water after rebuilding the engine, it wouldn't run correctly, power on on and off- would run ok for 5 = 10 secs, then like I had let the throttle off, then back into it. Felt like a fuel supply problem. I pressure and vacuum tested the fuel system to the pump, no leaks either way.

I checked the fuel pressure, was a little erratic at idle and bounced between 3 and 4-1/2 psi at revs. Ran a line direct from and fuel can, by-passing the entire fuel system. Made little difference, so I rebuilt the pump, which really didn't look that bad. Did the carbs at the same time. Adjusted them to have 21.5psi pop off pressure. Tested again, fuel pressure was steady at idle, but still erratic at revs, although better. This was drawing fuel from the tank, using the standard fuel system. Connected a 5/16 line directly to the pump from and fuel can and steady at 5-1/2 psi at revs. I had the gauge in the line to the mag carb.

So, I machined new plate for the top of the fuel tank, fitted a 5/16 pipe, and 1/4 barbs for the vent and return. I had a water trap with screen/filter from a small John Deere tractor that I modified and fitted. Has an integral tap too, just have to remove the front storage box to turn on and off. I am a mechanic, although I work on trucks, not jetskis! Have done a reasonable amount of 2 stroke work though. I am happy its not a fuel problem, there is plenty of fuel delivery when opening the throttle.

I think it is the stator, when looking at the wiring diagram, there are 3 of the 12 coils on the stator that are connected to the CDI green/red, red/white, blue/red. Not 100% sure on how it works, but I think one coil generates voltage at low revs with the other 2 bumping it up with revs? Being wasted spark, I think it doesn't have enough voltage at higher rpm, given the resistance between red/white and blue/red is under half what it should be. It sounds like it is bogging and missing when you open the throttle. Plus it had this problem when I got it and replacing the stator fixed it.

Do you know how this side of the stator works exactly? I would be keen to know

Sorry for the long explanation

[K447]

Have you seen this resource?

http://polarispwcknowledge.shorturl.com/first-things-to-do

In there is lots of info on how the blue Fuji engine works, including the electrical and ignition systems.

The ignition coil section is wasted spark, with all three coils firing together every time any cylinder needs to fire. But the ignition trigger side uses three separate signals from the stator to tell the module when to actually fire.

Another two stator coils provide the electrical power for the ignition system.

There is also a separate stator coil for battery charging.

[xlint89]

The detailed explanation is good, don't apologize for that.

I Would like to see some pictures of the fuel system you have. Something isn't adding up with that. The Mikuni pentagon shaped fuel pump have a 5/16" fitting on the fuel supply, not on the pulse (vacuum fitting). Also you stated you added a water separator from a John Deere tractor. There should have been a filter/water separator from Polaris already installed.

You mentioned you installed the fuel pressure gauge on the MAG carb. Was it installed between the CEN and the MAG carbs or after the MAG and going back to the fuel tank?

What year SLX 780 do you have? My manual is showing different pop off pressure readings for 1995 and 1996

Your problem is most likely the magneto, and it appears I'm fixated on the fuel, but I just want to get things sorted out with that too.

I had a magneto failing at higher RPM one time too. Once I replaced it, problem was solved. I believe the readings would change once the magneto started to heat up. That's not a fun part to change. It's almost as easy to remove the engine and swap the magneto as it is to replace it while inside the boat.

[Dodgeforce]

The detailed explanation is good, don't apologize for that.

I Would like to see some pictures of the fuel system you have. Something isn't adding up with that. The Mikuni pentagon shaped fuel pump have a 5/16" fitting on the fuel supply, not on the pulse (vacuum fitting). Also you stated you added a water separator from a John Deere tractor. There should have been a filter/water separator from Polaris already installed. Difference in terminology, by suction line, I mean fuel supply line, which is 5/16. Pulse is 1/4 on the pump and engine. With having the 5/16 barb on the pump, I wondered if the whole system is a bit small in hose diameter. I changed to the John Deere as the original fuel tap has 1/4 fittings, and the original water separator has no tap. It made changing from 1/4 to 5/16 simpler.

You mentioned you installed the fuel pressure gauge on the MAG carb. Was it installed between the CEN and the MAG carbs or after the MAG and going back to the fuel tank? No, between the fuel pump and carb

What year SLX 780 do you have? My manual is showing different pop off pressure readings for 1995 and 1996 1996
Your problem is most likely the magneto, and it appears I'm fixated on the fuel, but I just want to get things sorted out with that too.

I had a magneto failing at higher RPM one time too. Once I replaced it, problem was solved. I believe the readings would change once the magneto started to heat up. That's not a fun part to change. It's almost as easy to remove the engine and swap the magneto as it is to replace it while inside the boat.

.

[xlint89]

OK, thanks for the reply. Sounds like you got a pretty good handle on things. I was actually confused and thinking about the 650/750 carbs when i asked if you put the fuel pressure gauge between the MAG and CEN carb. Completely missed the fact it's a triple outlet fuel pump. Sorry about that.

If you're going to get a used OEM stator, i might suggest trying to source 2. Just to have 1 on back up, and if by any chance one of them arrives in non-working order. I try to keep spare parts on hand to limit down time when a failure happens.

[Dodgeforce]

Have you seen this resource?

http://polarispwcknowledge.shorturl.com/first-things-to-do

In there is lots of info on how the blue Fuji engine works, including the electrical and ignition systems.

The ignition coil section is wasted spark, with all three coils firing together every time any cylinder needs to fire. But the ignition trigger side uses three separate signals from the stator to tell the module when to actually fire.

Another two stator coils provide the electrical power for the ignition system.

There is also a separate stator coil for battery charging.

Could you check that link please, I cant get it to work??

[pascoea]

Could you check that link please, I cant get it to work??

You can use the base URL, http://polarispwcknowledge.shorturl.com/ , and click the "first things to do" at the bottom of the page.

[K447]

You can use the base URL, http://polarispwcknowledge.shorturl.com/ , and click the "first things to do" at the bottom of the page.

http://greenhulk.net/showthre...=1#post3182865

The subpages links across the bottom footer of the web site should continue to work for the time being.

HyperLinks from forum posts and within the web site pages - some will work, some will not.

Apparently even my forum signature web link is currently broken

[Dodgeforce]

Are SL750 stators interchangeable with SLX780? I am fairly sure I read on here somewhere they are (can't find it now!), but you have to use the SL750 flywheel as well? They look the same in pictures I have been sent.

[xlint89]

1994-1995 750 is interchangeable with the 780. (1993 used an analog design while the 94/95 and 780 use a digital system)

You can use a 780 flywheel with the 750 magneto just fine.

[Dodgeforce]

Great! How do you tell the difference between the analog and digital?