96 GSX won't exceed 4500 rpm maybe running rich?

[tbleier4]

Hey all,

I have a 1996 Seadoo GSX with the 787 Rotax, I just recently replaced the fuel lines from the crappy gray lines, cleaned out the fuel selector valve, changed the inline filter out (small filter before carb) and broke down the carbs to an extent. I didn't replace the pop of valve/spring but I did clean all the filters and ran some carb cleaner through. Never removed the fuel needles as I didn't want to mess with something that wasn't the problem.

Put everything back together and ran it this afternoon, plugged the hose into her and it fired up just fine on the trailer. A little smokey but ran good enough to warrant a test drive. Took it out and I would hit 4500 rpm and it wouldn't go any further, Throttle wide open and it won't pass 4500. Limped back to the dock and it was very smokey, the smell of exhaust was overwhelming but we made it. Got it back on the trailer and it ran fine under no load. Throttle wide open and it opened right up with a little bit of backfiring in the bottom end. The exhaust hole on the rear of the jetski is also oily/slimey.

Any suggestions would be great before I tear the Carb off again! I am running fresh ethanol free high octane gas. The injector oil is left over from last season.

Thanks everyone!

 

[JJinSC]

You really need to pull the carbs completely apart to clean. Not doing so and leaving parts in (that could be affected). while using carb cleaner is never a good idea. My advise is to take them completely apart and clean well. Do a pop-off test while in there to confirm and then also do a leak down test on each carb. Especially after complete re-assembly. Back firing definitely means something is not right. You could have an air leak. How were the carb base gaskets? Backfire could also be caused by out of synch carbs. Make sure adjustments are to spec on both carbs and carbs are synch.


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[tbleier4]

The carb base gaskets were replaced but I will get my hands on a complete rebuild kit as well as new pop off valves. I am familiar with the pop off test but not with the leak down test?

 

[JJinSC]

Do not replace the springs but do replace the needle/seats with OEM only if they need replacing. . Do not use aftermarket parts in the carbs. They have a bad track record on these carbs. Search leak down test on the forum. There are a couple good and recent posts regarding them. There will be two leak test. You want to test each carb individually to make sure needle/seats are not leaking and a second one after assembly to make sure that nothing is out of adjustment and causing the arm of the needle/seat to get pushed and leak.


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[tbleier4]

Great thank you! I'll give it a try and report back!

 

[tbleier4]

So time for an update, I did a complete carb rebuild. Removed all fuel jets high and low and reassembled to factory spec. The rebuild included new needle and seat as well. I pop off tested and both carbs were within factory specs. I also decided to get a RAVE valve rebuild kit for both RAVE valves. I took off the RAVE valves and the pto valve was soaked and covered in oil. I replaced the diaphragm and gasket and the small o ring. Put it all together by the book and took her out this morning. Idles great and runs very smooth up until 5000 rpm the. It won't surpass 5000. I know I should be getting much more power out of this craft which is so frustrating. Any suggestions guys?

 

[soccerdad]

A couple of ideas.
-Bad regulator? At the lake, open the front electrical box. Disconnect the red wire from the regulator/rectifier. See if it now hits the revs under load.
-sucking some air in the fuel lines?- Try running a new fuel line directly from the RES fitting on the fuel baffle pickup to the inlet of the fuel pump on the carb. That will bypass everything else.
-try trimming a half inch off each plug wire and screw the caps back on. Perhaps it is not strong enough spark to fire up top under load.
-Try new plugs
-What is your compression?
-Double check all wire connections and grounds. Especially in the rear electrical box and at the motor.

 

[Robj]

Rave isn't opening. You may have installed them incorrectly. There is a hole that needs to line up both on the gasket and rave housing. If that is blocked they won't open.

 

[tbleier4]

Well I trimmed back the plug wires and reinstalled the boots as well as re inspected my install of the RAVE valves and everything looked fine (holes lined up). I'm going to try the regulator/rectifier disconnect this afternoon as well as a direct line if that doesn't work and will report back.

 

[Matt Braley]

It sounds like a regulator. You can also put a volt meter on the battery while running to confirm this. Over 14v even while revving means it needs to be changed.

 

[Prime Target]

You're better off buying a new fuel selector switch than trying to clean the old one. It's a cheap and simple install. You'll never get them completely clean of the green stuff. Not sure if this is what's causing your problem but it surely could contribute to it.

 

[tbleier4]

This afternoon I disconnected the regulator/rectifier and there was no change. Didn't have enough time to do a fuel line direct from the res line. I'm gonna continue to research and save some money for more tinkering around so it may be a few days until I update thanks for the inquires though!