Hi all, I'm new to the forum and this is my first post. I just bought a 1997 XP and a 2000 GS and took them both to the lake yesterday for the first time. XP ran fine but I'm having an issue with the GS. I had to go through the carb when I got it because it had a bad bog. I found the accelerator pump was plugged up on the intake side so it was not working at all. I got that fixed and the ski sounded great on the trailer. On the water, it starts and idles fine and pulls hard out of the hole but when I'm going WOT in choppy water and the pump comes out of the water it has a major bog....bad enough to almost throw me over the bars. It's like the DESS key got pulled off or I hit the stop switch. Once it slows down a bit it catches it's breath I can hit it again and it pulls strong again. Seems to do it anytime I would expect to hit the rev limiter. I can hold it WOT while turning and keeping the ski loaded up and it never misses a beat so I don't think it is fuel delivery and the cut off is instantaneous so I'm thinking it has to be electrical. The ski does have an aftermarket MPEM, any known issues with aftermarket MPEMs? Any other suggestions?
Help! Rev Limiter? MPEM?
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jimmaki
Active Member
Does the rev limiter kick in on the trailer? Does it bog WOT on the trailer? How many RPMs at WOT unloaded? It it's not limiting or is limiting too high you could be seizing from too much air, too little fuel, at too high RPMs. If any of the above might want to consider an OEM MPEM or known working used one. I don't know much about aftermarket MPEMS other than some don't work like the factory ones. No beep beep at turn on for instance.
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No tach on the GS so I can't tell how many RPM before it happens. It will do it on the trailer but unlike the XP that just runs ratty when it hits the rev limiter, the GS shutdown until the revs drop and then it kicks back in. I originally thought fuel starvation too but it will run at WOT as long as the pump doesn't unload so I'm pretty sure it's RPM related. I'm thinking MPEM as well but I though I would throw it out there for comments before I spent the $$$ on the OEM MPEM and DESS programming.
You should go over all the connections. Shine, tighten, and put back with di-electric grease. DESS posts will fail sometimes and so do the keys themselves. The MPEM's they make are still gel filled so if they work I don't think a wave is gonna change that. I'd run it off the hose while I wiggle everything electrical and note what makes it shut down.
jimmaki
Active Member
When it starts to bog at high RPM, chop and read the plugs. If they're gray you're lean and may be seizing. If not, it's probably electrical.
The PO ran both premix and injection and I'm continuing the tradition until I can confirm that the injection is working correctly. I'm pretty sure it's not seizing. It probably did it 30 times on me when I had it out the other day and I got to where I could predict when it would happen. Any time the pump unloaded and I stayed in the throttle. I can do it on the trailer with no load on the motor. I went over the fuel system today looking for any issues but all looks good. Vents are open, fuel valve flows and works correctly and the hoses are all connected according to the labels on the tank and selector. The water separator did not have water in it.
So the saga continues. With the new MPEM it ran great but then I discovered that it had a draw and would kill the battery after a couple of days on the trailer. I did some checking and figured out that the draw went away when I unplugged the MPEM. It did not go away when I unplugged the rectifier. So I went back to the reseller and exchanged the MPEM for another new one. Put it on and the draw is still there but again the ski ran great.......for about an hour. Then it developed this new problem where I'm running WOT and suddenly it dies and then beeps like I just plugged in the DESS. It starts right back up and runs great but any high speed riding in rough water and it dies. I though maybe I was pulling the DESS loose but I can't make it do it without pulling the DESS all the way off so I don't think it's bad connection there. I put it on the trailer and yanked and pulled on every wire and cable and conector on the ski and couldn't make it do it. I'm thinking it's the MPEM again but I know the reseller is going to give me a hard time if I go back to him again. Thoughts?
I'm game for that if that fixes my problems but I know that there are lots of people running these aftermarket MPEMs. Has anyone had a good experience with them? I've had three of them so far and they've all had problems of some sort, none of them the same.
Who is Nick? I'd like to talk to him about a used OEM MPEM.
Who is Nick? I'd like to talk to him about a used OEM MPEM.
I'd like to add:
1 make sure the daam pilot circuit on that carb is clean (its been giving me lots of trouble on mine)
2 rev limiter for an oem one just bounces off it at 7100 rpm but never bogs and recovers
3 that draw could be the dess post swich inside the post. (as in it could be stuck on...) just disconnect the post or everthing going to the handlebars for that mater and see if the draw disapears.
4 if it dies like you hit the stop button while your playing in chop, its either the dess post or the start/stop button.
Nick: [MENTION=41828]Minnetonka4me[/MENTION]
http://www.seadooforum.com/member.php?41828-Minnetonka4me
1 make sure the daam pilot circuit on that carb is clean (its been giving me lots of trouble on mine)
2 rev limiter for an oem one just bounces off it at 7100 rpm but never bogs and recovers
3 that draw could be the dess post swich inside the post. (as in it could be stuck on...) just disconnect the post or everthing going to the handlebars for that mater and see if the draw disapears.
4 if it dies like you hit the stop button while your playing in chop, its either the dess post or the start/stop button.
Nick: [MENTION=41828]Minnetonka4me[/MENTION]
http://www.seadooforum.com/member.php?41828-Minnetonka4me
Embarrassing to say but it was a false alarm. I found out that my battery tray is all busted up and the battery had fallen over and in the process the negative battery cable came loose. I've ordered another battery tray but I was able to put everything back together good enough for another lake test and it ran fine. So now it's just the draw. I found out that if I pull the plug going to the stator the draw goes away too. I have not tried pulling the wires to the DESS post but I'll try that tomorrow. I have also noticed that sometimes I can't kill the engine with the stop button and I end up having to pull the lanyard so maybe it is my start/stop switch? It's been a really fun ski and it runs much better that I expected, just has a few nagging problems.
Yeah I just PU a 96 HX cheap with electrical issues, when I picked it up he told me he had replaced everything and it still didnt work. Got it home and it was all aftermarket garbage. Threw the old box out and put a replacement in and it fired right up.
jimmaki
Active Member
Ohm out the stator wires to ground and each other. It you get a low reading to ground the rectifier diodes could be leaking current through the stator.
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I'll check the stator wires the next time I have a chance to work on it. I did check this morning with all the wires from the handlebar disconnected and the draw was still there. I found that I can disconnect the connector on the top of the rear electrical box and the draw goes away. I assume that's because that is where the wiring harness gets its main 12v+ feed? I figure I can use that as a battery disconnect for now until I figure out what's causing the draw.
According to the wiring diagram, on the mpem pin 16 is the ground and 26 is the power. if you make jumpers and only connect those two to the mpem you should not see a load. if you do, that only means the mpem is bad.
your right about the plugs. on the rear box is the power and on the engine is the ground.
are you always seeing a load or is just for a few minutes ?
Im wondering if your just seeing a load until it times out.
your right about the plugs. on the rear box is the power and on the engine is the ground.
are you always seeing a load or is just for a few minutes ?
Im wondering if your just seeing a load until it times out.
I'm pretty sure the draw is there all the time as it will kill the battery after a couple days on the trailer. The draw goes away if I unplug the 4-wire stator connector. I looked at the wiring diagram and the yellow and yellow/black wires from that connector go to the regulator. Unplugging the regulator doesn't make the draw go away so I don't think it's those. The black and black/red wires go directly back to the MPEM. I tested with a meter and there is just under battery voltage on the black/red wire coming out of the MPEM, 11.8v vs battery at 12.8v. Question is, should there be voltage there and the stator should be breaking the draw is is the MPEM wrong for sending voltage out that wire in the first place? I think those wires go to the part of the stator that generates primary voltage for the coils. The MPEM is aftermarket and this is the 2nd one I've had on there and I had the draw with both of them.
Sounds like something is wrong but did you test with the plug connected or not?
with the plug off you will get that measurement.
On the engine with the plug off you should have 0 ohms to ground on the pin where the black wire goes and 70-80 ohms between the black/red and ground.
That black red wire goes through the mpem and back out directly to the coil.
The mpem taps into that wire for rev limiting purposes only. So if your seeing power on that wire, that means its the mpem that is either bad or different enough from stock that there may be something weird about its design.
Also it could be that there is an issue with the engine ground for the stator and the mpem is getting a ground through the ignition coil in the rear box instead of the engine.
Have a look at any older 717 mpem wiring diagrams. It will give you an idea of how the inside of the mpem is wired.
with the plug off you will get that measurement.
On the engine with the plug off you should have 0 ohms to ground on the pin where the black wire goes and 70-80 ohms between the black/red and ground.
That black red wire goes through the mpem and back out directly to the coil.
The mpem taps into that wire for rev limiting purposes only. So if your seeing power on that wire, that means its the mpem that is either bad or different enough from stock that there may be something weird about its design.
Also it could be that there is an issue with the engine ground for the stator and the mpem is getting a ground through the ignition coil in the rear box instead of the engine.
Have a look at any older 717 mpem wiring diagrams. It will give you an idea of how the inside of the mpem is wired.
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That was with the connector disconnected from the stator but the harness was still connected to the MPEM. I'll check the stator next time I get out there.
I measured 0 ohms to ground on the black wire and 62 ohms on the black/red but that's with a $9.99 Harbor Freight multimeter so I'm not sure that I would bet the farm on the accuracy of the measurement. It's not shorted to ground and it's not open, that's about all I would take away from that measurement....lol.
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