99 GTX running rough

[Tpolston]

My 99 GTX is running rough. Here’s what’s been done:
Carb clean rebuild
(Wouldn’t idle at all after this and would constantly die at low rpm’s. Runs fantastic at mid to WOT)
I then noticed the threads on the choke cable were snapped and it was adjusted completely at the ends of the threads barely hanging on. So I replaced the choke cable.
(Now runs at idle decently when feathering the throttle, I think the idle without throttle feathering is too low, at mid to high 900 rpm’s but sputters out. It now has a little trouble at low to midrange rpm’s but if you feather the throttle a little bit and then hammer it, it screams like normal)

EDIT: I forgot to note that if I play with the choke at low rpm’s (barely pulling it out) it has no trouble but then when I get into it, I have to let the choke back in to let it breathe enough to get the full potential of the engine. It seems obvious that it’s something with the air/fuel or something with the carb but I don’t know what.

Anyone have any ideas?

 

[Noahsfixingbrokedownskis]

Did you use the Mikuni OEM kits on rebuild, all other kits are junk in general. Also if you have old gray fuel lines I would change them out, and did you set the carb pop off pressure? Finally seadoo 2 strokes on land needs to idle high at 3k. In water it will drop to 1500. So turn up your idle by adjusting the idle screw. Don't adjust the carb jets from stock adjustments. 95% of adjustments are idle screw, clean fuel system and correct carb rebuild procedure. Also you need to be very careful to follow all the instructions exactly under the carb rebuild thread on this forum that goes through everything step by step. If the idle screw, fuel lines, and Mikuni kits and following the rebuild thread exactly doesn't help than let us know what your experiencing. This forum has helped me with my gsx and gti 96 machines a ton.

 

[Tpolston]

Did you use the Mikuni OEM kits on rebuild, all other kits are junk in general. Also if you have old gray fuel lines I would change them out, and did you set the carb pop off pressure? Finally seadoo 2 strokes on land needs to idle high at 3k. In water it will drop to 1500. So turn up your idle by adjusting the idle screw. Don't adjust the carb jets from stock adjustments. 95% of adjustments are idle screw, clean fuel system and correct carb rebuild procedure. Also you need to be very careful to follow all the instructions exactly under the carb rebuild thread on this forum that goes through everything step by step. If the idle screw, fuel lines, and Mikuni kits and following the rebuild thread exactly doesn't help then let us know what you’re experiencing. This forum has helped me with my gsx and gti 96 machines a ton.

The Mikuni kit was used. Fuel lines on carb were swapped. I also changed fuel filter which had a bunch of crap in it. Also not sure what carb pop off pressure is I guess I need to research that.

 

[mikidymac]

Sounds like the small pilot holes are clogged in the carb.
Did you follow the carb rebuild thread to the letter?

 

[Tpolston]

Sounds like the small pilot holes are clogged in the carb.
Did you follow the carb rebuild thread to the letter?

Not sure because it was my dads that he ended up selling to me when we bought our lake house. I would assume so. I took it out the other day and adjusted idle screw and reset the small low speed screws on the carb to the factory recommendations. It will stay idling around 1000-1200 rpm but if you give it gas it dies instantly most of the time. Sometimes you can feather the throttle and it will bogg down and then catch back up and then you can hammer it. Otherwise you have to let it die and then start it again and immediately when it starts feather the throttle and you can go. It runs awesome anything over 3k rpm but that low range is just not good. I’m sure what you’re saying about the small Jets is it. I took the carb out for them when they rebuild it and it was s bitch so I don’t really want to again lol but may be a good fall project since it runs well enough to function at least.

 

[mikidymac]

Just keep running it lean, the engine seizing will let you know when you should have fixed the carbs correctly.

 

[Grim]

I would suggest taking carbs off and checking to verify pop off is right and it doesn't leak. Also idle should be at 1400 in water. Your idle can effect low speed bogging. Make sure your low speed is at factory spec, high speed at factory and idle at 1400, see what she does after all that.