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99 GSX-L won't accelerate.

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chrisml

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Hello. This is my first post. I figured I'd look for more input because I'm very stumped.

My Sea doo is a 1999 GSX Limited with 202 hours and no performance mods that I'm aware of.

Least year my Sea Doo was getting harder to start. Since at that point I had only replaced the really easy to access fuel lines I decided it was time to replace the rest of the lines, clean the carbs, and do some general maintenance. I just wanted to do preventative maintenance to make sure I didn't explode it. The engine has had water in it 4 times in the 3 years I've owned it but it was always cleared within an hour and then I would give it a good hard run to evaporate the water in the crank case. Besides being hard to start the Seadoo would do 6700 rpm no problem, about 58mph on the GPS and had such a good hole shot that it would actually shoot out of the water if you gunned it hard enough.

I've put a new battery in it. I think that was why I was having such a hard time starting last year was an abused battery, or maybe a slightly weak starter. I was able to do a compression test with a borrowed gauge and read about 133 on both cylinders. I believe the target is 135 on a good 947?

I took the carbs apart and just cleaned them but they weren't that bad. I didn't touch either the high or low adjusters. The worst part was a tiny bit of green goo in the PTO carb's internal filter. Mag carb looked pretty darn clean to me. I didn't change anything and didn't check the pop off. While the carbs were off I also replaced all remaining tempo fuel line, and cleaned out my selector valve. I didn't actually take it apart - i just sprayed it and turned it back and forth and then blew it out with compressed air. Is that thorough enough? It didn't seem bad at all.

At one point after I did the compression test I had it started to run it on the hose, but before I could get the hose turned on it started to do a lean runaway. I yanked the lanyard and the choke and choking it managed to kill it.

I had it out at the lake and got it started, no real problem there. We went out and I noticed the acceleration wasn't what it used to be. I figured it was just cold so I waited a bit and kept trying to let it warm up. It never got "Warmed up". I could give'r and the engine would basically want to bog down and die. I could feather it a bit and then hold the throttle down and it would eventually get up to about 5000 rpm. But it would idle all day. So while we were tinkering we strapped it to the trailer and tried again, it was like it had completely woken up. easily revved up to 6500 rpm or so and seemed smooth. So I untied it and went for another boot, it would barely get to 4000 rpm and was bogging badly.

So after that I took it home, and started checking everything I can think of. I checked the accelerator pump was squirting (yep). I cleaned the raves, cleaned and gapped the plugs (to .24). Trimmed the spark plug wires and re-attached the boots. took the carb apart again on the jet sides only and removed the adjusters, cleaned everything again, set the adjusters to the recommended settings that I could find, which was low adjuster 1.75 turns out, and high adjuster all the way in. Put it back together, drove to the lake and tested it again. it would idle again no problem but then wouldn't accelerate. I did find it would idle perfectly at 1500rpm, High idle seemed ok (like 2000-3000 rpm waws attainable) and then when you give'r it would bog and then idle would become difficult until i shut the engine off for a few minutes. While I was out I tried to choke it while it was bogging to see if it was running lean, but having the choke out at all made it worse. This time it's bogging strapped to the trailer too.

I tried adjusting the the low speed adjusters 1/4 out, and tried again, same thing. then another 1/4 out and tried again, still bad. I then re-set them to 1.25 turns out, still bogs. I gave up and came home again.

I pulled the carbs and their mounts off today and checked the reed valves, they all look good. Maybe a touch oily. I had noticed that my raves were oily/carbony when I took them off, but when I pulled one last spring they were clean as could be.

After installing the carbs I've been leaving the return valve off and using my compressor to pressurize the tank until fuel comes out the carb return port. Is that the best way to prime these or is there a better way?

Any suggestions to fix my bogging issues?

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In my attempt to contribute back, here's my suggestions for removing the carbs.
Remove the electrical box, battery, and choke cable before trying to remove the air box.
Remove the air box extensions.
Get the air box out the back.
Remove the return fuel line and the pulse line.
Remove the PTO carb's bolts with an allan key, use the key to remove the bottom bolt on the mag carb and then use a 1/4 drive ratchet with a 3" extension and a 6mm hex drive bit to remove the upper bolt. Feel for the indents in the airbox bracket to find the bolts. There are 4 indents where the bolts that hold the carbs on sit, and 4 indents where the air box bracket screws sit.
Pull the bolts, seperate the carb from the engine and make sure you don't lose the gaskets in the bilge. Then turn the carb upside down and remove the fuel line and the throttle cable.
Pull everything else out and put it on the bench where you can see what you're doing.
 
I think i found my problem. I took the carb off one more time to double check that the check valve circles in the fuel pump side were in the right place and change the pulse line because I wasn't sure if it was leaking. When I put the carb back on and blew in the return line to pressurize the tank again I heard the sound of water running. That sound was actually the sound of gas pouring out the "fuel in" side of the PTO carb. This would also explain my absolutely terrible fuel economy. I think I was worried about stripping screws or I was planning to criss cross while tightening to make sure I didn't deform anything and just never went back for the second round of tightening. Stupid mistake. I won't know for sure until Friday when it goes back in the water, but I'm feeling pretty good now.
 
Hey there, what was your final resolution. I have a similar issue going on. Just wondering if you got yours figured out. Thanks
 
Yep, putting the carb back together properly fixed that issue. I tweaked the low screws about 1/8 of a turn and now it goes from idle to WOT no hesitation. It's still hard to start and I think the problem is the fuel is dripping past the needle valves and sitting in the crank case under the PTO cylinder. I've heard this can happen when the machine is stored on an angle and mine is winched up a wooden ramp when not in use. I didn't actually do a proper re-build, just a cleaning, so my needle valvs may need to be replaced and a proper pop-off test done, or my fuel tank vents may need to be replaced. Apparently if the tank isn't vented properly the fuel can become pressurized and travel into the carbs and force it's way past the needle valves. The day I tested it was 35 degrees outside and when I went to start it the next day I had to pull the spark plugs and it pumped a bunch of fuel out.
 
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