[bryoung]

My 99 Ultra 150 with 94 hours suddenly got slower on take off and top speed. It won't leap a foot out of the water when punched. Slow to step up in speed.
It feels like it's starving for gas. New plugs @73 hours. Oily #1 plug. Cleaned plug but have not tried it. Any other suggestions? Carb adjustment? Clogged water intake?
My speedometer did indicate 82 but I know its inaccurate.

 

[JayDawg]

Replace all of the plugs with new ones and see if that does not solve the problem. I have the same exact jet ski as you right down to the same year model and these things sometimes will go through plugs rather quickly but it is a cheap fix too. If it is still doing that, then replace your fuel filter. If the problem still exists, then clean your carbs. After that, check compression and your jet pump, impeller and shaft for damage. If the problem still persists, then I will ask more questions.

 

[bryoung]

99 Ultra 150

Wow, that was a quick and exacting answer. I really appreciate that..I have only 14 hours on the plugs. Do you know a cheap source for the plugs. I paid $25 each @ NAPA. The #1 cylinder oils plugs. Is there a lean adjustment where I can get to it? What does the black carb adjustment knob on top of engine do? I don't think it's the filter because it doesn't bog down when throttling and when you come off the throttle it speeds up. I felt a miss while idling when I first notice the power lose. Later, idling at the ramp, I didn't notice it. There is no impeller noise or shutter from debris.

I guess I need a shop manual.

I'm a shade tree mechanic with a beer pocket book. This is my first jet ski. I didn't realize what a fun monster the 99 ultra is.. It kicks other jet ski butts.

 

[JayDawg]

I believe I run NGK BR-9's in my Ultra. Go to any place that sells atv's and jet ski's and they should have them for around $5.00 per plug. The garage light is burnt out in my garage so when I have light tomorrow, I will go and check the exact plug that I run in mine. Your engine is a 2 stroke engine so the plugs might have a small amount of oil but should not have a whole lot. If your #1 has a lot of oil, then check your compression because you could have bad rings.

 

[JayDawg]

The plugs are the NGK BR-9ES.

 

[bryoung]

99 Ultra

I looked in the manual and this is the plug I have and they recommend. Mucho bucks.
PLUG-SPARK,R6918C-9(NGK)SOLID. I found the plugs online for $9.00. I'm ordering them.. I'm was thinking about the oily plug. I let someone else ride the jet ski twice and they always complained about it running sluggish. I realize he was leaving the choke to full ON. The manual said that would foul plugs. I keep the jet ski near lake Ouachita in Arkansas, 222 miles away. I'm near Memphis, Tn. I'll try to replace the oily plug with the best of the three used spares I kept or new ones. Hope it's not a ring... I'll figure it out in a couple of weeks before it gets cold..

Thanks, Bob

 

[JayDawg]

The 99' Ultra 150's took a different plug than all of the other model years but you can run the ones I listed above without any issues.

 

[bryoung]

99 Ultra Plugs

Interesting...
The original plugs for a '99 were NGK R6918C-9. You can call Kawasaki with your Hull ID Number at (949)770-0400 to find out if you have the updated ignition to take the cheaper BR9ES plugs. If your Ultra originally came with this plug then stick with it. You could loose performance and potentially cause engine damage. For now, I guess I'll stick with the expensive ones. I need to get my hull # and call the Kawasaki people to verify.

Thanks, Bob

 

[JayDawg]

I don't have the updated ignition but have been running the BR-9's since the first day I replaced my plugs and have never had an issue. I will call that number though and make sure for certain though that the ignition has never been changed.

 

[JayDawg]

Interesting, I just called Kawasaki and I actually do have the updated ignition. I guess it was a change mid way through their build that year. I was simply told by my dealership in San Diego it was okay to run the BR-9's but they never even mentioned there was an ignition upgrade. Anyway, for all of you 99' Kawasaki Ultra 150 owners out there, here is an easy way to check if you have the upgrade or not. On your V.I.N. number, after the KAW, if the next numbers are higher than 41804, then you have the ignition upgrade. Mine was, so I am good!

You learn something new everyday!

 

[bryoung]

99 Ultra

It was the plugs. Runs like a champ. Someone I let drive it left the choke on..fouling the plugs. I got a GPS to check the speed for this spring.
Thanks for your help.:appl:

 

[JayDawg]

Glad you got it figured out!