Help - 1996 GSX Bogging Down

[mhix]

I've recently picked up a 1996 GSX. Everything on it (other than the battery and possibly the VTS motor) is original and it has 147 hours on it. The first time I had it out this year it ran reasonably well. It was a bit rough in the bottom end but the plugs were in need of a change.

Last weekend I had problems getting it up onto a plane. I changed the plugs and it seemed to run well the first time I had it out. I think it might have just been good timing and not actually the plugs. It starts with no problems and seems to idle well. When I give it some gas it starts to chug and almost sounds like it's not detonating properly. Sort of muffled. If I back off and hit it again a couple of times I can get it going and it runs strong at WOT from that point on. Nice and smooth in the top end. I did notice that in the first minute or two of getting it up to full speed it hiccupped a couple of times and felt like it was going to stop. It seems like it runs better the longer it's been running.

I've been reading through the forums here looking for similar issues and it looks like it could be a number of things. From what I've pieced together:

1. I do have the original gray gas lines. I'm planning on replacing these next weekend if I can.

2. The spark plugs do not appear to be fouled. The old ones I took out were chocolate brown and the new ones were whitish brown after running for about 30 minutes.

3. I've read that a bad rectifier could cause similar symptoms. I'm going to try pulling the fuse next weekend and running it.


I'm a bit of a noob when it comes to this but it feels like a fuel delivery issue. Does anybody have any other suggestions as to what might be causing this? Dirty carbs? Any help is greatly appreciated.

 

[kustomkarl]

Welcome to the seadoo forum mhix. First thing I would replace all the Gray fuel lines with black replacement fuel lines. If the clamps need replacement do so too at the same time. Use stainless steel replacements. I would clean the carburetors and pay special attentions to the small internal filters in the carbs. I betcha that is the problem the way it is running. Be careful not to tear the diaphragms in the carbs or you 'll have to purchase a rebuild kit to replace them. Keep us posted on you progress and how it works.

Karl

 

[mhix]

Thanks Karl. I'll post an update when I look at it next weekend. I don't have a lot of experience with small engines but have lots of experience tearing things down so I should be alright if I grab a shop manual. There's apparently a good Seadoo mechanic in the town where I'm storing the GSX if I run into trouble. It's good to have an idea of what's wrong ahead of time so I don't get ripped off.

 

[mhix]

Made it up to the cottage this weekend and pulled everything apart. I replaced the fuel lines but the old gray ones looked pretty clean. The filters in the carbs were also really clean. There was barely anything in them. Put it all back together and still have the same problem. Where should I look next?

 

[kustomkarl]

You won't see anything in the lines but the internal filters collect crap and get clogged. Did you clean all of the carbs of or just stop at the filters? Did you adjust the carbs according to the manual...1 1/2 turns on the Low speed and "0" on the high speed adjustment. Lets start with basics...What is the compression of the cylinders? Here is some info on doing a compression test. 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 guage, 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. After we have a couple things known, it will help us solve the problem.

Karl

 

[mhix]

I stopped at the filters and didn't mess around with anything else. I did notice it was idling a bit high on the trailer so I adjusted the low speed screw accordingly. I haven't done a compression test but that's the next thing I'll do.

One other thing I did notice was the engine felt like it was missing with the throttle wide open. I think it might be the rev limiter as it looks like it hits 7,200 RPM on the tach and then misses, hits 7,200 and misses again and on and on. Are these things supposed to be running over 7,000 RPM? I noticed the manual mentions 6,950 RPM at the top end.

 

[kustomkarl]

To adjust the idle speed on the trailer it should rev at about 3000 rpms and in the water is should rev about 1500 rpms. to Do not use the low speed screw to adjust the IDLE SPEED it will cause a seizure due to the wrong mixture! Idle and low speed is 2 different things. It is possible that the carbs are just out of adjustment. Keep us posted.


Karl

 

[mhix]

Had it out again over the weekend. I didn't have time to do a compression test but noticed something strange while it was bogging down on me. If I hit the VTS up or down buttons while it's bogging down the engine surges like it has power again. Could this be an electrical problem?

 

[ducky71887]

1996 tigershark Monte Carlo

I purchased this jet ski a few weeks ago. It runs fine. I have found that when i add more weight to it, like another person it will not plane out, it acts like it is bogging down. It has no problem planing out when it is just me on it. It is rated as a 3 person, 490 weight limit, I am very confused, does anyone have any insight?

 

[JESSECONSOPOLUS]

on my 96 gsx the center plug on the box up front was corroded. it caused mine to do almost he same thing. i pulled the plug and cleaned all the terminals. plugged er back up and runs great. i thought at first my rave valves were in need of a cleaning but it turned out to be an electrical issue. the ski was acting funny in the water, sometimes 2 beeps off the key sometimes nothing. sometimes it would stay running even with the key out and holding the kill switch down. i had to disconnect the ground to kill the dang thing. this is all with a new key and post so i knew it couldnt be that. moisture built up in the plug i guess. but i cleaned all the connections and she ended up being a good ski.