99 SeaDoo Gtx LTD bogs on initial acceleration and once it hits 5600 rpm will drop back down to idle

[Jweish]

I just bought this a couple weeks ago and the guy gave me a receipt showing he had the carbs rebuilt and new plugs. If I keep the rpms in the high 4000s or low 5000s it will cruise fine for the most part. But if I go WOT from idle it will bog at first and then accelerate fast up to aprox 5600 rpm then rpms will drop drastically and sometimes die. So far I replaced fuel vent valves, blew out the vent lines, cleaned out the fuel selector valve, cleaned and inspected rave valves and water regulator valve. Found water in air silencer box, so I cleaned and dried it out, found the clamp on he hose from the muffler to the resonator was loose and the hose slipped off so I remedied that. But still the problem persists.

 

[kenfyoozed]

Does it still have the grey fuel lines? The shop that rebuilt the carbs are they reputable? Sounds like mine before I rebuilt the carbs.

 

[Jweish]

Does it still have the grey fuel lines? The shop that rebuilt the carbs are they reputable? Sounds like mine before I rebuilt the carbs.

The fuel lines are grey but they say Chevy Silverado on them so they were all replaced, I checked the ends of some of them and they were clean but I’m thinking about changing them anyways. I don’t trust the shop that rebuilt the carbs because they left off an air intake boot, and they had the idle set to barely over 1k rpms and where the carbs mount to the engine I can tell they are old gaskets. So I think you are right that removing the carbs and going thru them myself is my next move. I adjusted the idle and set the low screws to 1.75 turns but I couldn’t see the high speed screws.

 

[mikidymac]

Replace the fuel selector and make sure the carbs have genuine mikuni kits in them.

 

[kenfyoozed]

Replace the fuel selector and make sure the carbs have genuine mikuni kits in them.

Make sure you get genuine mikuni kits. Before I rebuilt mine i order a rebuild kit that was much cheaper but while waiting I ran across this advise. I ordered the genuine kits and you could see a big difference in o ring profiles and gasket thickness. It cost more but its done right.

 

[Jweish]

Ok so I’ll replace the fuel selector and the fuel lines and order genuine Mikuni carb kits. I know the fuel selector doesn’t close all the way cause when I had it out and cleaned it I could blow air through it in the off position. Any tips or good videos i should follow on the carb removal/installation and rebuild process? I do have the shop manual to follow

 

[mikidymac]

I like this one personally... Carb Rebuild Thread

 

[kenfyoozed]

shop manual is nice but the one posted above is better with pics.... color pics are worth everything to me

 

[Jweish]

Thanks so much for the awesome tutorial, I am leaving for vacation for 2 weeks but when I get back I will definitely be using this tutorial and I will let you know if this fixes my seadoo problems

 

[Jweish]

Update: rebuilt my carbs with Genuine Mikuni kits and new needle/seats changed out all the fuel lines, and fuel selector valve and seadoo runs perfect.... except it maxes out at ~4500 rpm in the water, doesn’t bog down and doesn’t ever drop rpms like it used to but once it hits 4500 it just stays there. On the trailer with a hose it hits 7000 rpm at WOT.