750 SXi won't run right on the low end. Please Help

[SXI Pilot]

Hi guys. I was hoping that someone could help me. I just bought a 96 750SXi (copletely sock) and took it out for the first time yesterday. It took a little while to get it started but when it did it seemed to idle ok. As soon as I tried to ride it though I noticed the problem. Between 5-40% throttle it had no power, would bog down and eventually stall. I had to choke it to get it running again. It seemed to run alright in the higher throttle ranges but every time I let it slow down it would die on me. To keep it running at slower speeds I'd have to put the choke partially on sometimes and when it didn't stall out it ran like crap. I checked the plugs and they looked OK. The guy I bought it from said he had the carbs rebuilt about 2 hours ago and that it ran fine which it seemd to do in his driveway. I don't know much about Jetski carbs but it seems that it's running too lean. I really don't know though. Maybe the low speed needle is not adjusted correctly. I'm not sure where the adjustments are for this or how exactly to do it. If anyone can help me I'd greatly apreciate it. Thanks in advance......Later

[mphsjeep]

Re: 750 SXi won't run right on the low end. Please Help

Something to try.....sounds like your low end is not adjusted right. On your carbs there are two adjustment screws on each. They are verticle to eachother.....the ones on the bottom are low end and the top high end. Turn the low end ones counterclockwise one eighth turn....I had the same issue with mine and that fixed it...good luck!

[john zigler]

Re: 750 SXi won't run right on the low end. Please Help

definately sounds like a "lean condition" like mphsjeep said, try turning you low speed screws out some. you can go in 1/8 turn increments.

just because the carbs were just gone through, doesn't mean they were done correctly, or not in need of attention still. if you are not capable, maybe take them to a good shop to get them done again.

could aslo be a air leak, from carb, intake gaskets, crank seals ect.

you should also check all of your fuel lines, pulse line, fuel tank pick up, fuel selct. sw. and tank vent. i would recomend getting a good shop manual. you may be even able to get one at your local library.

good luck. zig

[Relentless1]

Re: 750 SXi won't run right on the low end. Please Help

It sure sounds like it may need the carbs pulled off once again to be sure all the gaskets and passages are clean, including the jets, and needle and seat.

In all my racing career I never had to "rebuild" any of my carbs, I would only take them apart and clean them, then reassemble using the same gaskets.

Inside the carb, is an internal barrel filter. It will get clogged with debris and make your boat run lean. Most shade tree jetski mechanics will throw a "rebuild kit" in the carb, never taking out the barrel filter and cleaning it of debris.

The only way to tune your boat is in the water under load.

The low adjuster is basically only an idle quality adjustment. Anything after that is on the high adjuster& pop-off pressure. Although at full throttle, the suction will pull fuel from the low side circuit, under the butterfly.

Adjust idle while the ski is on the trailer in the water. Turn the low adjusters to sync them to be exactly the same amount of turns out, so you will know where your at. Now turn the low adjuster on one carb and get the engine to run the best. You may have to adjust the idle adjuster. Now adjust the other carbs low adjuster to acheive the best idle quality.

Now with the high adjusters 2 full turns out go ride. Idle for about 10 seconds and grab a hand full WOT. If it falls on it's face and dies, you need bigger high jets, If it gurggles and then takes off, come in and turn your high adjusters in 1/8 of a turn and try again. Keep at it until you get that snap off of idle. Do not go too far. Or you will burn a piston, from a lean situation.

[DankBud]

Re: 750 SXi won't run right on the low end. Please Help

Kawasaki's dont have that "barrel filter" But there is a filter on bottom of needle and seat. I'd just rebuild and clean. I tend to rebuild mine about every 2 yrs and clean 3-4 times a year. Other than that adj. the low as described above a few times.

[SXI Pilot]

Re: 750 SXi won't run right on the low end. Please Help

Thanks guys. I pulled the carbs to clean 'em up and found out that three out of four needles were stuck. I was able to break one free but the other two wouldn't budge even after being soaked with PB Blaster for a few days. I tried using some vice grips and actually snapped one needle off trying to turn it. Yes, they are that stuck:( . Maybe there is a way to fix this but I can't think of one. The only thing I can think to do is replace the carbs but I'm having trouble getting a decent set of used ones. There was a set on ebay but it went for a lot more than I thought $235+ shipping. They were off a 2000 SXi Pro and came with a manifold and air box that I don't need. Was this a good price for these? Anyone on here have a set they want to sell? They're the Mikuni Super BNs. Any help will be greatly apreciated. I really want to get this thing on the water before I need a wetsuit. Thanks......Later