1996 gtx slowing up

[Helios1326]

Hey this is my first post. I got a 1996 seadoo GTX from my uncle. It only has 73 hours on it. It runs great, I had it tuned up at the dealer when I first got it at the beginning of the season. It starts out running about 40-45mph at about 6500rpm. Now sometimes later in the day it starts running 55mpg. Any ideas of how to keep it running more consistant?

 

[derek]

i assume you mean 5500 rpm. cause if that seadoo gets 55 miles per gallon i wanna buy it! anyway, later in the day it is 1000 rpm slower. is it an air temperature thing, or is it that it was running hard all day? cooler denser morning air will run a too rich fuel mixture better than warmer thinner afternoon air. so, if you put it in the water at 3 in the afternoon when it is 90 degrees and the ski is rested-but still runs 5500 instead of 6500 then you need to lean the mixture a little. A LITTLE!! too lean burns aluminum instead of gasoline. guess where it gets the aluminum from?

 

[Helios1326]

This is after being run for about 2 hours. The rpm doesn't seem to change at all. The temp is pretty constant over those 2 hours. So do I still need to lean the mixture? And if so how do I do that? I haven't really worked on a jet ski.

 

[kustomkarl]

Don't lean the mixture... I would do a compression check and look for an internal problem. You'll need a compression tester. Go to Auto Zone. I think they sell for like $25.00. The compression gage, will screw in the cylinder head in place of the spark plugs. To test compression, remove both spark plugs. Place spark plug caps on the plug cap studs near the cylinder head to ground the empty caps. This completes the circuit of the ignition electrical system and prevents any electrical problems from the caps being un grounded. Using the correct adapter for the threaded end of the tester,( same length of the spark plug threads length)screw in the tester in one plug hole. Hold the throttle wide open. Push the start button. Watch the compression gauge, when it peaks out at the most compression, let go the start button. Read the psi number. I would do it 3 times to be sure it is accurate. Check both cylinders the same way. The ideal compression is 150 psi per cylinder. If it is less, it's not a problem as long as they are close to being the same. If the psi is less than 90 it might need be time for a tear down and a rebuild. If the psi in 1 cylinder is say 140 psi and the other is 80 psi you need to tear down and repair. This difference is a lot and there is a problem. I hope this helps you.

Karl

 

[Helios1326]

Thanks for the information Karl. :hurray: I'm going to try to look at it this weekend!

 

[kustomkarl]

Keep us posted on you progress. Do you have a seadoo shop manual? If not here’s an idea for you. You could join as a "premium member". As a premium member you can down load a authentic seadoo manual from the seadoo manual library. In the library is a variety of manuals for almost all years and models. You can view as many as you like on line as a PDF file, or download it and print it for your personal and private use. There are operator manuals and repair manuals for you to do your own repairs on your seadoo. The repair manuals have everything from troubleshooting, repair procedures to winterizing. It contains wire diagrams torque specs and pictures for disassemble and assemble instructions. In the spec sheets it tells everything needed to maintain oil changes, spark plug gaps, carburetor rebuilds and impeller wear ring tolerances. Click on the "Seadoo Manuals" link at the top of the page for more details. If you need any help or get in a jam, we are always here to answer your questions too. Premium members get priority when it comes to getting quick detailed answers.


Karl