1998 Seadoo GTX Limited Edition Carb Adjustment

[mike.metzger6]

Recently purchased a non-running 1998 Sea-Doo GTX, limited edition. Had the motor rebuilt by mechanic and rebuilt the carburetors myself using Mikuni kits. Took it out for the first time today and had some bogging issues. Low end seemed to be fine. Only had issues around 5000 RPMs and up but not consistently. Sometimes you can roll into the throttle take it to 7000 RPMs and cruise at 60 miles an hour other times at 5000 RPMs plus it would seem to break up and bog. Used the specs online which were 1.5 turns out for the low speed and zero for the high speed. My question is if I’m having a bogging issue at higher RPMs but not consistently, would I turn the low speed screw further in by maybe a half a turn or further out a half turn. I’m thinking half a turn out because it’s possibly starving for fuel? And half a turn out would open the jet and it would receive more fuel? Or is it getting too much fuel and causing it to intermittently bog?

Or should I be looking at the hi side jet and adjusting that off zero. Any help is appreciated

 

[burtshaver2021]

I would leave the carb settings at stock. Is that a 787? Have you looked at the rave valves? If they are really gunked up or a hole in the bellow can cause these symptoms

 

[mike.metzger6]

I would leave the carb settings at stock. Is that a 787? Have you looked at the rave valves? If they are really gunked up or a hole in the bellow can cause these symptoms

It’s a 951 motor. It was just rebuilt and rave valves were cleaned and inspected. I’m thinking it has to be a fuel issue. I just rebuilt the carbs, did new fuel lines and cleaned the filter. However it has been sitting for probably 2 years at previous owners with a half a tank of gas in it which is what I cruised it on today which I guess could also be a slight issue if it never had any stabilizer added to it.

 

[burtshaver2021]

Agree, drain that fuel out. You said the carbs were rebuilt. We’re genuine Mikuni parts used? The pilot and main jet circuits cleaned well? I feel they get passed over sometimes during carb cleanjng/rebuild Have a look at Mikidymac’s carb rebuild thread for a full description.

 

[burtshaver2021]

osdparts.com is a great place to order genuine Mikuni carb rebuild kits. I’m thinking maybe yours were not Mikuni? order the back to OEM kit with new needle and seat. OSD will probably ship it out the next day, I’ve always had great service from them

 

[mike.metzger6]

Agree, drain that fuel out. You said the carbs were rebuilt. We’re genuine Mikuni parts used? The pilot and main jet circuits cleaned well? I feel they get passed over sometimes during carb cleanjng/rebuild Have a look at Mikidymac’s carb rebuild thread for a full description.

Yes I did the carbs with Mikuni kits and pulled the jets and screen and cleaned everything well with carb cleaner before reassembling

 

[burtshaver2021]

Only other thing I can think of would be the rectifier, I guess they can cause symptoms like this. There’s a test you can do, not sure exactly how it goes but something like take a volt reading at the battery while it’s running, too high or to low of volts indicates a bad rectifier or you can also disconnect the red wire to the rectifier while I’m the water. If symptoms go away then you’ve found your problem, just know that your battery will not charge with the red wire off. Good luck, hope you get it figured out.

 

[POPPS]

I would check for charging, go through the rav’s, and carbs with a fine toothed comb.

 

[burtshaver2021]

I would check for charging, go through the rav’s, and carbs with a fine toothed comb.

Hey Popps, can a lean condition cause issues like the poster is talking about? Not being able to get the rpm’s up past 4500. I’m thinking not, I’m thinking the engine would run away with a lean condition from sucking air from the oil seals, carb gaskets, fuel filter,

 

[POPPS]

Your situation sounds like not enough fuel is going to the engine. A bad rectifier could also cause your symptom. sticky rav’s as pointed out could cause your symptom. Opening the high speed will not solve the issue. If the bottom end pilot circuit was lean, then yes,,,it can run away. I once read a thread of your issue, hit a wave (no load), , rpm goes up…and then back in the water (full load),
The solution was carb related, and some was related to the anti-syphon valve, I apologize, it was years ago,,,and my recall is fuzzy, Rav’s easy to fix, charging to do,,,then pull the carbs if necessary, Just wondering a fuel pump clear check valve is cracked?

 

[burtshaver2021]

Your situation sounds like not enough fuel is going to the engine. A bad rectifier could also cause your symptom. sticky rav’s as pointed out could cause your symptom. Opening the high speed will not solve the issue. If the bottom end pilot circuit was lean, then yes,,,it can run away. I once read a thread of your issue, hit a wave (no load), , rpm goes up…and then back in the water (full load),
The solution was carb related, and some was related to the anti-syphon valve, I apologize, it was years ago,,,and my recall is fuzzy, Rav’s easy to fix, charging to do,,,then pull the carbs if necessary, Just wondering a fuel pump clear check valve is cracked?

Thanks Popps