[franzl]

2. Ride the boat at a constant 1/4 throttle opening for about 1 minute and then quickly open the throttle fully, there should be no hesitation and the engine should not show signs of being loaded up. If it hesitates, it's lean; if it's loaded up, it's rich. The first test is to check pop-off pressure, the second test is checking the correctness of the low speed jet size. Take the time to ride the boat slowly and thoroughly test your jetting changes. After a jet change, it takes the engine a few minutes of use to completely respond to the change. more

[30dirtybirds]

Kawasaki Jet skis are know to have issues with their round body carbs. They are difficult to tune and give many people many issues. The Jet ski Carb for the 550 Jet Ski is a Mikuni 38 mm Carburetor. The main problem comes from their setup. Standard Carbs have a only a high and a low needle for idle adjustments and high RPM. Tuning a Jet Ski carb is extremely difficult and requires that you do it in the water. Below you will find information on how it works and how to tune your jet ski.

[mixedunicc]

MEASURING POP-OFF PRESSURE
You can measure pop-off pressure with a "pop-off" pump, available from Mikuni through your dealer. more

[bidcoin]

IDLE STOP SCREW
The idle stop screw is used to adjust the idle speed (rpm) by opening or closing the throttle valve. Refer to your watercraft owners manual for the correct idle speed. As a rule of thumb, adjust the idle speed to approximately 1100 rpm.

[ruenma7411]

Please note all testing must be done wet, so fill the pressure tubing up with gas mix or light machine oil (sewing machine oil is cheap).

[Vladimir]

Click on a type of carb, then when the parts diagram pops up, scroll down to the variations of the carb. When you look at each carb you will see different metering springs, throttle butterflys, main nozzles and needles. more

[MCNARS]

The pop off pressure determines the fuel pressure in the control chamber, ie. the fuel pressure the jets actually see. [links]

[joshg56]

Pulled the plug from #3 and its sparkling new, no steel of fuel or anything. The other two, while only a month or so old, have a nice brown/black tinge to them. This is when I tested spark btw and confirmed #3 has spark. If I adjust the low end screw the engine does not respond in any way but if I adjust one of the other two I can get the engine to change rpm.

[kathybrendan962]

The issue I have is with the starboard engine. Its not as smooth as the port and doesnt rev as high as port. Not going to go into too much detail there to prevent mis-diagnosis. Basically, I think I've confirmed that the #3 cylinder isn't achieving combustion. I thought it was spark at first but testing that showd spark arcing if I grounded the spark plug to metal while turning over the engine. I also tried disconnecting the boot from the plug as the engine ran and there was zero discernable change in sound or rpm or anything but if I pulled one of the other two boots off a cylinder (1 or 2) it was definitely noticeable. If I put one of the other wires from 1 or 2 on 3, nothing happens. I started the engine on one cylinder, first on 1 and then on 2 only but when trying 3 only, all it does is turn over. Using one of the other cylinder plug wires results in the same no start using only #3.

[m0mchil]

Hi guys. First time post. Bought an LS2000 that had both engines replaced about a year ago. After a little TLC (replacing oil lines, performing compression checks which showed 118-120 on all cylinders, replacing fuel filters, new plugs, installed primers into the fuel lines to manually prime before start, took exhaust apart and broke it down to the three parts and cleaned all the gunk and buildup that was in there and put back together with new oem gaskets, and a few other maintenance items on the boat) both engines start and run. Cooling is great.

[laurenexbush]

So, my question to you all is, does this confirm that fuel isn't reaching this cylinder and if so does that make this a carb issue specific to this cylinder and carb? Is there an "easy" way to test this? Like, is it OK to pop the flame arrestor cover off and dribble fuel down into the carb with the oil that dribbles down or would that cause some sort of backfire? I just want to see if I get fuel in there, does the engine respond in any way, and if so, then I know its that carb.

[allinvain]

[twobitcoins]

here

[packetloss]

Everyone wants to have a machine with perfectly tuned carburetion, but not everyone knows what that means. Technicians describe perfect carburetion as being "seamless" throughout all throttle settings. That means you can hold the throttle at any setting without experiencing any sputtering (from being rich) or any hesitations (from being lean). Furthermore you should be able to move swiftly from any throttle speed to another, without experiencing any "stumbling" or "surging". Starting should always be instant, idling should always be smooth and steady, and acceleration characteristics should always be consistent and predictable. more

[mike_3296]

Pop Off Pressure - The pop off pressure is not an adjustment that exists on the carb, but rather a specification that is a combined function of the needle valve size, and the spring rate of the float arm spring. This specification has a wholesale effect on the fuel metering in the 0 - 40% fuel range. Because the pop off pressure has this far reaching range that overlaps with several other metering ranges, we consider it a fundamental starting point. here

[pyrrhos]

LOW SPEED ADJUSTER
The low speed adjuster is used in conjunction with the idle stop screw to adjust and maintain idle speed and smoothness. Experiment turning the low speed adjuster in and out in small increments until a smooth idle is obtained. As the idle stop screw is turned in our out to raise or lower idle speed the low speed mixture is also affected. For clarification, if the idle stop screw is turned out to lower idle speed, this action increases manifold pressure slightly and richens the low speed mixture so that a mixture adjustment may be required. The low speed adjuster is very sensitive and adjustments should be made in small increments only.

[atonmack87]

When does it become necessary to adjust pop-off?
When personal watercraft come from the factory they have fairly high pop-off due to the fact that they also have somewhat restrictive air intake systems that cause the engine to generate very high manifold pressures; the higher the manifold pressures, the higher the pop-off pressure required to properly regulate the fuel delivery to the engine. As you modify or change your watercraft's flame arrestor to a less restrictive type you will most likely start to experience a lean hesitation caused by a decrease in manifold pressure. This change will require an adjustment in pop-off pressure to regain crisp throttle response. Because most
aftermarket flame arrestors are less restrictive than stock, you will need to decrease pop-off to compensate.

[macktyalor]

The bendix is the gear that connects your starter to your your flywheel. This gear engages the flywheel when starting your motor and disengages the flywheel when turning the engine off. more

[ircicq]

Before anything else, CHECK YOUR BATTERY. A weak or dying battery is the culprit in almost all jet ski starting issues. here

[jessw1]

Do you hear a very distinct, and very annoying, weeeeennnnnngggggeeee weeeeeeennnnnnnngggggggeeee sound when trying to start your ski?

[RobHu]

Time to take a look at the Bendix.