DO NOT Bypass the Engine Compartment Temperature Sensor
DO NOT Use Standard (BR8ES) Type Spark Plugs In A 1999 Ultra
Like increased compression, aftermarket flame arrestors are a favorite PWC bolt-on performance part. In the case of a pump gas compatible Ultra using the stock CV carbs, aftermarket flame arrestors are not a good idea. This is not a function of the flame arrestors being poorly designed, but more a case of the carb design not accommodating the change. The stock CV carbs have a conventional throttle butterfly just like all other PWC's. However the CV carbs also have a vacuum operated slide that is driven by the inlet tract vacuum. A freer breathing aftermarket arrestor allows air to enter the carbs more easily, thus reducing the vacuum that lifts the slides. This means that at most throttle positions, the vacuum slide (and it’s fuel metering needle) are considerably lower in the carb bore than they should be. The result is some very serious lean conditions in the mid range (particularly at 6200 rpm). No carb jetting to date has been able to correct these lean conditions. There are always exceptions and a few people have had no problems using aftermarket flame arrestors on the stock CV carbs, just be aware of the risk.
About The Ignition System And The Temperature Sensor:
In an effort to get the maximum power out of the Ultra 150 engine, Kawasaki engineers developed an ignition system that has multiple timing curves. Not only do all three cylinders have different timing curves, but the ignition “mapping” delivered to all cylinders varies based on throttle position, a function dictated by the throttle position sensor (or TPS). When the TPS “sees” a swift opening of the throttle, the ignition delivers very advanced timing for a brief amount of time. As peak rpms are achieved, the timing switches to a slightly more retarded mapping. However the timing required for detonation-free partial throttle cruising is even more retarded than the full rpm mapping. When the TPS “sees” the throttle slowly lifted from wide open to partial, the ignition selects a much more retarded mapping to stave off detonation at mid range cruising speeds.
All in all, this ignition works well to allow strong overall power along with high detonation resistance. However it must be kept in mind that the Kawasaki engineers laid out this ignition mapping to be optimum with stock compression, and with the fuel mixture of the stock carbs. This means that “liberal” increases in compression can easily result in increased detonation risk.
The most significant difference between the 1999 through 2001 Ultra is the 2000 model introduction of altered ignition mapping that allows for the use of less expensive spark plugs. (In my experience, the less aggressive timing curve on the 2000 models slows them down a bit. I have easily beat every 2000 Ultra that I have raced, 6 total.)
The Ultra has an engine compartment temperature sensor that can advance the entire mapping by about 3 degrees when it “sees” exceptionally high air temperatures in the engine compartment. The intent of this sensor is to maintain good performance in areas with poor air density caused by high air temperatures. Installing a resistor in place of this sensor “fools” the ignition into seeing high temps all the time, hence offering the more advanced timing all the time. Group K's on-water detonation tests showed that this mod can be safe “sometimes” on an otherwise stock machine. However when combined with higher compression heads, the detonation risk is dangerously high. Group K considers this to be a 100+ octane modification only.
There has been much discussion of the unique (and expensive) spark plugs used in the 1999 Ultra. The technical feature that makes these plugs so unique is their exceptional resilience against porcelain damage from potential detonation. We recommend against the use of standard (BR8ES) type spark plugs in stock 150s. We furthermore consider the use of the stock R6918C-9 spark plugs to be absolutely mandatory for any modified 1999 Ultra.
I have read all of the official paperwork from Kawasaki. Click here to view the actual documents. There have been three recalls on the 1999 Ultra. The first, dated 9/1/99, was to replace an over torqued nut that holds the steering cable where it exits in the pump cavity. The second, dated 12/17/99, was an exhaust system modification. The third, dated 10/26/00, was for the fuel tank vent hose. The only recall on the 2000 Ultra is for the fuel tank vent hose. When I find out if there are any on the 2001 models, I will post it here.
I did the repair on the steering cable nut myself. I got the new nut and borrowed the special tool from my dealer. The reason for the recall was, someone on the assembly line over torqued the large brass nut that secures the steering cable where it exits in the pump cavity. Failure of this nut could cause a loss of steering control. The replacement nut is exactly the same and there is a special socket, which is over a foot deep, that you use with a torque wrench to accurately tighten it. The original nut looked fine and I returned it and the tool to my dealer and they filled out some paperwork.
The exhaust system modification recall is due to people who ride in shallow water or beach their Ultra. If a pebble, or too much coarse sand, is forced into the cooling system, it can clog the two 4mm water passages that are in the end of the exhaust pipe (stinger). Water flowing through these cools the rubber hose that runs from the stinger to the water box. Kawasaki tuned the exhaust to run with a minimum amount of water in the water box. The repair consists of drilling out one of the holes to 7mm and plugging the other with a blind aluminum rivet. This makes it harder to clog the passage. If done incorrectly, it increases the amount of water going to the water box and increases the back pressure, which takes away a lot of power. I have talked to several people who had the exhaust recall performed and they were very angry at the power loss. Others who have had it repaired properly have had no noticeable loss of power. The people who had it done said it took away about 5 MPH top speed according to their speedometer. I realize that no PWC speedometer is accurate, however, it can give you an idea of relative speed changes when no hull changes (ride plate, intake grate or sponsons) have been made. I ride in the ocean, often inside the break line with lots of stirred up sand, and I have never had a problem of any kind in 80 hours. I just don't ever beach it, start it or ride in water less than 2.5 feet deep. If you had the modification performed and you have a loss of power, a 2000 model stinger should cure the problem. I spoke to an owner who had experienced the power loss after the modification and he demanded that they put a new original part back on. They said the original part number was no longer available and they replaced it with a year 2000 part. He said that this restored the power. A water strainer will help prevent anything from clogging your cooling system and I would add one instead of doing the exhaust modification. It can be beneficial to add one to any brand of PWC, except for the new models with closed loop cooling systems. It attaches on the cooling water line anywhere before it enters the engine. Your local watercraft or RV dealer should be able to get one or you could try www.denniskirk.com, click on "Watercraft" and search for "strainer". They charge $18.99 for it. I would put a direct link here, but the URL changes often. The Ultra has a 1/2" I.D. cooling line. Here is a photo of it installed in my Ultra.
My strainer installed.
The fuel tank vent hose recall is due to some people filling their fuel tank to the very top of the filler tube. Then it sits in the water or on the trailer and the sun heats it up and the expanding fuel has nowhere to go except out the vent line and it drips into the engine compartment. I wonder if one actually exploded when it was eventually started? It is advisable, for all boats and PWC, to ventilate the bilge before starting. The repair for this is somewhat more involved. The fix consists of three parts. First, a plastic buffer pipe is pressed into the filler neck of the fuel tank. This increases the volume of air in the tank when it is full and decreases your fuel capacity by about half a gallon. Stock, the vent line goes through the steering shaft and exits inside the handlebar pad assembly. If fuel were to discharge from the vent line, it would drip down the inside of the handlebar pad assembly and then drip down a hidden panel under the glove box into the engine compartment. In some cases, the vent hose can slide out of the steering shaft and fall into the engine compartment. The second part is a U shaped pipe that goes in the end of the vent line and prevents it from sliding out of the steering shaft. The third part is removing the glove box panel and attaching a piece of molding to the hidden panel, which would divert the fuel that might drip into the engine compartment. It would then drip on either side of the glove box, instead of into the engine compartment. These modifications will not cause a loss of performance. I have never had a problem with this and I came up with a simple solution that does not reduce fuel capacity. I DO NOT recommend that anybody do what I did. If your Ultra blows up it is not my fault, have the dealer do the recall. That said, I was able to pull the vent hose out of the steering shaft without taking anything apart. I then drilled a hole in the flat fiberglass surface near the oil fill cap. I installed a water bypass fitting in the hole and attached the vent hose to it and I used a hose clamp. If fuel were to discharge from the vent hose, it would drip down the side of the deck and not into the engine compartment.
About The Break In Procedure And Top Speed:
Break in your Ultra slowly and resist the temptation (very difficult) to race anybody, or see how fast it will go, until you have at least 10 hours on it. Mine didn't really achieve it's full speed potential until it had about 40 hours on it. I believe this is because the hard Nikasil plated cylinders take more time to break in and loosen up than cast iron cylinder sleeves.
I use a female friend's '99 XP Limited for comparison and she is about 100 pounds lighter than I am. (I wish I could justify spending $2500 on the Stalker Radar Acceleration Testing System.) At 10 hours, I was barely faster than her. After about 40 hours, I can easily pass her any time and she is a good rider.
Run 50 to 1 premix (13 ounces of oil in 5 gallons of gas) for the first 5 hours (in addition to the stock oil injection) and don't go full throttle at all, just constantly vary your speed. Ideally, put it in the water and idle around for 5 to 10 minutes (depending on the water temperature) to warm it up. Then continuously vary the throttle position, not giving it more than a quarter throttle. Do this for about a half hour and then shut it off and have a sandwich and a soda and admire your nice new machine for about another half hour. When it has cooled down completely, warm it up again and continuously vary the throttle position, not giving it more than half throttle. Do this for about an hour and then let it cool off again. Now warm it up again and don't give it more than about three quarters throttle until you have 5 hours on it, just continuously vary the throttle position. From 5 to 10 hours only clamp (go full throttle) it for a few seconds at a time. After 10 hours, clamp away! I believe in a conservative break in procedure and I ALWAYS warm up all my PWC engines (or any engine) for a few minutes before I clamp it. Even if I just take a 5 minute break, floating and talking to my friends, I don't just start it and clamp it. Cold seizures can happen and it accelerates engine wear.
see the navigation frame at the top, or if you are still in another site's frame.