98 gtx 787 problems, need help please.

Myself · 06-24-2009, 10:27 PM

When you put the lanyard on you get 2 short beeps. Then the ! warning light starts flashing and the display reads LOW FUEL. There is plenty of fuel in it so I'm guessing the float is bad. It starts right up and idles great. It is perfectly rideable at lower speeds. When you try to open it up it runs up to about 35mph but not as fast as it should. Then the engine turns to 6000 rpm then jumps back down to 4500 rpm. If you keep the throttle pegged it will just continue to do this back and forth RPM thing. The whole time never running faster than 35mph. Today it happened as soon as I tried to ride it. Last weekend it ran great for about 45minutes before it happened, and hit 54mph. I have unplugged the overheat sensor, checked the fuel tank vent, did a compression check, and checked out the jet pump.This machine has 109 hours on it. What could be causing this, and does anybody have a link to electrical specs that I could check with a meter?

parts_maniac · 06-25-2009, 12:29 AM

i would check charging voltage. hook your meter to battery terminals and start unit. see what battery voltage goes to when you rev unit a few times. should be over 13 vdc. if not try regulator.could also be stator.

chudzikb · 06-25-2009, 06:26 AM

The obvious questions are cleaned the carb filters, and changed the fuel lines and replaced/cleaned the selector valve?

bills86e · 06-25-2009, 08:05 AM

Quote:

Originally Posted by Myself

When you put the lanyard on you get 2 short beeps. Then the ! warning light starts flashing and the display reads LOW FUEL. There is plenty of fuel in it so I'm guessing the float is bad. It starts right up and idles great. It is perfectly rideable at lower speeds. When you try to open it up it runs up to about 35mph but not as fast as it should. Then the engine turns to 6000 rpm then jumps back down to 4500 rpm. If you keep the throttle pegged it will just continue to do this back and forth RPM thing. The whole time never running faster than 35mph. Today it happened as soon as I tried to ride it. Last weekend it ran great for about 45minutes before it happened, and hit 54mph. I have unplugged the overheat sensor, checked the fuel tank vent, did a compression check, and checked out the jet pump.This machine has 109 hours on it. What could be causing this, and does anybody have a link to electrical specs that I could check with a meter?

With a METER, with it running, more than 15v tells you to replace the rectifier.
All those observations, usually points to the stator coils have small ferro-magnetic
particles interferring with the waveform out-put of A/c current. Simply remove the
stator and carefully vacuum out these particals.
Most important is a compression test Check your plugs for correctness and
color, dry or wet, to determine a lean or rich condition. Please post your results.

Myself · 06-25-2009, 03:09 PM

How about some specs so I can ohm out the stator. Color wire to color wire please.

Bill O'Neal · 06-25-2009, 03:19 PM

Concentrate on the easier stuff first.
A simple voltage test with the engine off, measure voltage in the battery. Then start the motor and rev to 5500 rpm, read it again. It should read higher than when it was not running, but never more than 15VDC. That establishes that your charging system is working or not working.
I am a bit confused here. You say it is a 1998 GTX. The only 787 engines used in a 1998 GTX are RFI motors, no carbs. Tuff to clean a carb if you do not have one.

If it is an 787 RFI, it may need a new rectifier, as those things eat rectifiers for lunch. You probably have nothing else that needs fixing if it needs a rectifier.

But if it is a 1998 947 powered Sea Doo, you may have other issues to deal with.

What is it ? A 787 RFI or a carbureated 947 ? Or maybe it is a 1997 model with a carbureated 787 ?

Myself · 06-25-2009, 06:39 PM

Sorry, its a '97 787 carbed.

Myself · 06-25-2009, 06:45 PM

OK just checked voltage at the battery. 12.39 volts. Started it up and revved it to 5500 and it goes up to 16.6 volts.

Bill O'Neal · 06-25-2009, 06:52 PM

Replace the rectifier and it will start running good again.

Myself · 06-25-2009, 07:22 PM

OK thanks.