98 gtx limited

[philams@hotmail.com]

hello,
I have been working on a 98 gtx limited and cannot find the cause of my problem.
it will run great in the yard on a hose, rev fine starts up with just a bump of the button but when I put it in the water it will not go over 3000 rpm, I have inspected and replaced the RAVE valves, selector switch, plugs and gas lines. last night I noticed that when I unscrewed the fuel cap it had a little pressure, is that normal?

 

[Coastiejoe]

Pressure is better than a vacuum.

If the vent did not work then when the fuel pump placed a draw on the fuel the tank would eventually not allow fuel to get to the pump due to acting like a straw. Once you suck the air out it wants to collapse and nothing can get through it. The fuel tank works on the same principle.

Disconnect the regulator as when they fail they can act like a rev limiter. It will not charge while disconnected but it will tell you if that is the issue.

 

[Seadoobuddy]

Hi & welcome to the forum.

I was going to say it's your regulator until I saw the last sentence about gas pressure. I would check your gas tank vent line first to see if it is blocked in any way.
Report back with your findings.

 

[philams@hotmail.com]

vent line is clear, but the regulator on the other hand? I am new to these so could you tell me where to unplug it and what it looks like?

 

[philams@hotmail.com]

looked all over for the regulator, all i can come up with it is in the mpem? is that true?

 

[Coastiejoe]

looked all over for the regulator, all i can come up with it is in the mpem? is that true?

Some are internal but can be replaced with an external design that Seadoo has.

I can't answer the question until I get home. Basically some can unplug and others (I have heard) must be cut.

So if no one answers this b4 I get home then I will do some digging.

 

[Coastiejoe]

Here is a link to help test it.

http://www.seadooforum.com/showthread.php?50055-How-to-test-voltage-regulator

 

[Coastiejoe]

Another on location (but may not be the same for your ski).

http://www.seadooforum.com/showthread.php?31491-Testing-the-rectifier

 

[Coastiejoe]

And a you tube video on it.

http://m.youtube.com/watch?v=kS1c53_xz_4&desktop_uri=/watch?v=kS1c53_xz_4

 

[philams@hotmail.com]

And a you tube video on it.

http://m.youtube.com/watch?v=kS1c53_xz_4&desktop_uri=/watch?v=kS1c53_xz_4

well I started the ski, brought up to 5500 rpm and got a 14.8 reading on the meter, I did however find a fuel line kinked and leaking that is coming from what I believe is similar to the vacuum advance set up on a throttle body carb. not sure it it will make it all better or not. will test on lake tomorrow.

 

[Coastiejoe]

A regulator can fail and still charge. It has to do with an A/C issue which affects how the ski runs.

But,,, fix the fuel line. If it sucks in air or leaks fuel it can seriously affect how the ski runs.

 

[philams@hotmail.com]

Will do! Thanks for your help, I will update the situation tomorrow. Thanks again!

 

[P.W.R 96 xp 800]

******************

 

[Mekanix]

well I started the ski, brought up to 5500 rpm and got a 14.8

Sounds like it was boosted with a running car or a charger on boost... The regulating side of the regulator/rectifier seems to be shot if its anything above 13.5v +- 0.3v. At 14.8v that's really close to doing damage to the mpem!!

At that level the mpem does weird things and could fry if prolonged.

Check for AC voltage next time and avoid revving it if you get any. You shouldn't get any. That also points towards a faulty RR or stator if you do but that voltage is just a big red light


Also, this is one thing it does when the regulator goes bad.
[video=youtube;kS1c53_xz_4]https://www.youtube.com/watch?v=kS1c53_xz_4[/video]

Seems allot like your 3000 rpm rev limit.

 

[philams@hotmail.com]

well I put it back in the water yesterday after fixing the fuel line. did get an improvement on take off but still no luck overall. I have literally done everything I can think of besides changing out the regulator (because it is built into the mpem and about $450 part just to 'hope it fixes it" ) The comment about the 14.8 voltage frying the thing is really beginning to make more sense and a bit worrisome. I would really like to test it or bypass the regulator somehow before shelling out that amount of $$. Still on the search for a way to bypass it. Another reason for the fried mpem would keep the digital display from shutting off and read funny??? Cant be a good sign!

 

[Mekanix]

Well, I downloaded the manual and took a look at it.

Looks like a regular 3 phase charging system.

I would think you could disconnect the 3 yellow stator wires and run them to a normal regulator. Use the negative of the regulator and connect it to the engine as a ground.
Connect the red output wire through a 15 amp fuse to the Red/Purple wire going into the mpem.

That should effectively make it a normal separate charging system.

I haven't tried it. This is just what I can see looking at the diagram...