1997 GSX rev limits at ~3300

[Antz2813]

Alright so I picked up a 1997 Seadoo GSX knowing it wasn’t quite running right. It starts right up in or out of the water no problem. Out of the water it seems to run just fine. Revs up and idles fine. On the water it revs up to around 3200 rpms and sounds like it is bouncing off the limiter. Coasts 5-10mph. Doesn’t sound like it’s bogging down due to a fuel issue. My first thought was to swap out the rectifier. Old one was corroded. Swapped it out with a new OEM one and no change besides the display no longer reads low voltage and no red light. There is also no change in performance if I disconnect the red wire of the rectifier. Would a bad stator cause the limiter to occur? I’m thinking I would show low voltage if the stator is bad. Can it get stuck in a limp mode? Compression 135 on front and slightly under 130 for the back. Does not have grey fuel lines and I cleaned up the carbs as well. Any help is greatly appreciated! First ski but I have worked on plenty of boats and cars so I like to think I’m mechanically inclined. Just not sure where to go next. Hoping it’s not the MPEM.

The ski also has some other issues that don’t bother me but I’ll list just in case they could be related
-no beeps at all, with key or pushing start a few times
-VTS is shot, while unit corroded and it blows the 7.5 instantly( VTS now disconnected)…I haven’t tested it since disconnecting.
-Speedo sometimes doesn’t work altogether and sometimes just jumps around then goes down to zero . LCD screen does work

 

[Antz2813]

Update: Picked up 7.5 fuses and they continue to pop even with VTS 6 pin connecter unplugged

 

[POPPS]

Are uou charging 13 to 14 volts at the battery.

 

[Antz2813]

Yes, with a fully charged battery I’m reading a bit below 13v at idle then jumps to a little above 14 when revved up

 

[POPPS]

almost sounds like it missing,,ignition coil,,,check uour spark,,,should be nice bright blue/white,,,however..i partially blocked/plugged carb can oroduce the same symptoms,,,happened to me on a 720 at WOT

 

[POPPS]

Your charging numbers are fine,

 

[Antz2813]

Thanks Popps! I will do what you mentioned above and report back. Can I assume my stator is fine then?

 

[POPPS]

I am not good at electrical,,.but would appear your stator/ reg are okay...could be the cdi?,,,but there are far more knowledgeable guys out here on possible electrical,,,i would backtract on that 7.5 fuse that goes,,,

 

[Antz2813]

So I figured out the 7.5 fuse. When disconnecting the VTS I only disconnected the 6 pin connector and forget the power/ground connector. Disconnected that, no more blown fuses. Also got a new cdi and plugs. Spark looks stronger than before swapping everything but I’m still running into the rev limiting issue.

Any ideas on where to go next?

 

[mikidymac]

What CDI did you buy?

 

[Antz2813]

Sorry misspoke…new ignition coil not the cdi. Correct me if I’m wrong but for this model I cannot replace a cdi without replacing the whole mpem

 

[mikidymac]

Correct, it has an integrated MPEM.

Have you checked the voltage regulator? It is external on that ski.

 

[Antz2813]

Yes, I replaced with a new one. Charging numbers are good. I have also tried the test where you disconnect the red wire of the regulator too and no change

 

[jdmskidda]

I had a similar issue . I think mine would go to 3500 rpm then hit the limit , I changed to a set of carbs that were off a good runner and the problem went away