Carb problems on my kawi jet ski?

Question

my jet ski only runs with choke half on and it only goes about half the speed it should.....and i have to start it up by putting gas in the intake. could this be fouled plugs....or is the feul pump bad? PLEASE HELP!!!!!!

Answer 1

If that's a 2-stroke, you're damaging it by running it like it is.

running with choke and starting when primed with gas pretty much rules out everything except gummed up carb.

solution is to remove carb, disassemble, soak overnight in carb cleaner, blow through passages with compressed air (or aerosol carb cleaner), reassemble with new carb kit, reinstall, adjust slow speed mixture s***w.

Answer 2

You are not really damaging if you are pouring pre-mix in as a primer. Straight gas, or starting fluid isn't good, it "wipes" the cylinder walls.

There is a very easy way to eliminate fouled plugs from the equasion. I'll let you figure that out.

From reading your other posts, I can only assume you have a '78 Kawasaki JS440. It would be helpful if you post that info as it can make some difference.

You are describing a fuel starvation problem. It is possible the CDI/coil assembly is weak, but they usually fail with a no run condition. The plug wires themselves can burn, I have seen several do that. They can be replaced with SOLID CORE universal wires (7mm) from an auto parts store. They are not made as replaceable, but it is possible.

Your trouble is most likely in the carb itself. You say you have had it off and built. Are you sure it was built right? This is a Mikuni carb with an integral fuel pump and must be assembled correctly. One boo-boo I see often is the check valve (thin clear plastic sheet) put in before the gasket and cover. The gasket goes first, then the valve, then the cover.

The jets must also be setproperly. The low speed needle should be initially turned out 5/8ths of a turn, and the high 3/4ths of a turn. They will rarely need further adjustment.

Be certain all diapraghms are turned the proper way.

The "float arm" (no float, but that is what it is called) has to be set right. When installed. it should be parallel to the face of the carb, and the button on the diapraghm operates it.

Be sure the pulse line is not loose, kinked, or cracked.

Poor crankshaft seals can also cause this problem, and this is common especially on a 30 year old ski. If the seals leak, you won't have the needed vacuum to operate the fuel pump. The are not to difficult to replace, be eliminate all other possibilities first.

Here is a website with exploded diagrams that my be helpful;http://216.37.204.206/Mcmart/Kawasaki_OE...

I have several of the stand-ups, and although they can be finicky, they run well when properly set up.