carb tuning for a jet ski HELP PLEASE

[sl1cksNsk1n1es]

didnt know where else to post this one but if anyone is familliar with a 88' kawasaki 650sx, or how to put a carb on and tune it up please help.

i have put the carb on and when i crank the motor there is no fuel going through the fuel lines. i am pretty sure the fuel pump works...

how do i get fuel too the carb and once i do where do i go from there?
The carb is about as simple as they get, single barrel with an idle screw, choke and two screws for tuning...

i was told one of the screws was for top end and the other is for low end... Is this true???

PLease help summer is here and i really wannaget in the water

ps. any other tips for the ski would be great

[curtis73]

Who makes the carb? Mikuni? We need to know more. I'll assume that its a 2-stroke.

If there is someone here who has direct experience with 2-stroke carbs they might be able to help, but the quickest answer is a motorcycle or ATV shop. Just go straight to the garage bay and politely ask your question and you should get an answer.

There should be three screws in some fashion. Most modern 2-stroke carbs have a high jet, a low jet, and an idle setting. Sometimes the idle is set by simply using the throttle cable adjuster, but not usually.

Also are you sure you're looking at the right fuel lines? 2-stroke carbs have multiple overflow and air bleed tubes that are clear, but the fuel line itself is black rubber. You won't be able to see fuel in it. Pull the plug and see if there is gasoline on it. If there is, you're definitely getting fuel. Hold the electrode of the plug against the metal of the engine and crank. See if you get a hot spark. 2-strokes notoriously foul plugs because they burn oil with the gas. Also, if you foul a plug or flood the engine, don't try cleaning it or burning the gas off... just get a new plug. Ignition systems on newer cars are really hot and they'll send a spark no matter what the plug looks like, but 2-strokes are barely making enough. If the plug has been flooded, has carbon on it, or just looks "used" try a new one. They're $3, so its nice to have a few spares on hand.

[MagicRat]

Good post.^^

These are 2 stroke engines.


Your fuel pump may not be any good. These pumps are usually a 'pulse' type, that is, they use the varying positive and negative pressure in the crankcase to actuate a rubber diaphram to move the fuel through valves. These diaphrams usually need replacing every 2 years or so to ensure proper operation. Your dealer may have a rebuild kit for the fuel pump; it's easy to install.

Make sure the plastic hose from the pump to the crankcase is in place. Note, this particular hose is NOT a fuel line, so make sure your hook up is correct.

I would also recommend you take the carb off and at the very least remove the float bowl and clean it up with spray carb cleaner and clean up the jets and the float valve. All these recreational engines are notoroius for having problems due to lack of use. Stale fuel in the carbs evaporates and leaves gummy residue that plugs everything. Without a cleaning; you can get fuel to the carb but it will not do any good.

You can use clear plastic fuel line in this system which makes it easy to see where the fuel is. It sounds as if this machine has some already. Replace this line if it seems hard or brittle; it rarely lasts more than 2 years in good shape.

Finally, get a service manual for this thing. It will be extremely valuable for repair and tuning.

[sl1cksNsk1n1es]

i do have new NGk plugs that i put in... the carb is brand new but it is stock it is the same one with the letters around it.

Why are there two places for fuel lines?

The three tuning screws are (C - top) (B - idle) (E - bottom) ... once i do get fuel to the carb is there any order i should do it (example: tighten the screws all the was and work my way out or vise versa) one acouple turns ahead or behind?

do you know if one is air and one is fuel? if you do could i put the choke on and just tune the fuel and deal with the air after i get the fuel right?

thanks for lookin pictures will be there soon

[sl1cksNsk1n1es]

one more ? this ones kinda out there but... the stand up skis were not made with a cut off switch that shuts the engine down when you fall off. they just kinda slow down and then spin in a circle. is there a spring that pulls the nossle to one side or the other, or does it just do that. because i noticed that when its out of the water it just stays where you leave it.

[curtis73]

I think its just how the jet flow works. I think the nozzle has a little venturi in it that squirts a little flow sideways which kicks it over.

Installing a kill switch is pretty easy if it makes you feel better. You can buy the kill switches with a cord and its a pretty easy one-wire installation. Drill, silicone, and some wire and crimp connectors and you're in business.

[UncleBob]

I used to be a jetski/motorcycle/generator/marine/lawnmower mechanic (heh, the job title was annoying) and I worked on these older kawi's, but that was many many cases of beers ago. If I had the carb infront of me, I could tell you what screw does what, but its nearly impossible to tell just looking at the picture.

A good general rule for any screw adjuster on a carb, whether its air or fuel, 2 turns out is a good start. IE, screw it all teh way in until it seats *lightly!* and then turn it out 2 full turns.

And the best advice I can offer? Get a manual. It'll give way better discriptions on what screw does what than my faded memory could.....