How to Adjust the Carburetor in a 1999 Yamaha GP1200 WaveRunner

When you think of adjusting the three side-draft carburetors on a 1999 Yamaha GP1200 WaveRunner, you may imagine some arcane process that involves needle valves, multiple jets and obscure tools. Nothing could be further from the truth. There are only two adjustments available -- one to the carburetor linkage and one to the trolling speed -- and you only need two common tools and one instrument that any WaveRunner owner should already have.

Things You'll Need

  • Shop tachometer
  • Flat-head screwdriver
  • Foot-pound torque wrench
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Instructions

    • 1

      Use the latch under the back edge of the seat to remove the seat. Locate the gray tachometer lead extending from the multipurpose electronic module that is located on the left side of the engine, above the starter. Plug the gray wire into a shop tachometer. Place the lanyard lock plate in the kill switch, but do not push the "Start" button.

    • 2

      Loosen the remote throttle stop screw -- a flat knob with a slotted top and knurled or fluted edges -- found atop a tubular steel housing to the left of the intake duct, at the rearmost part of the carburetor linkage. Turn the remote throttle stop screw counterclockwise, using your hand or a flat-head screwdriver, until its tip no longer touches the throttle lever at the rear of the carburetor bank. Count the number of turns needed to separate the throttle stop screw from the throttle lever.

    • 3

      Look into the carburetor bores to ensure the throttle valve on each carburetor is fully closed. Tighten the two linkage adjustment screws on the No. 1 and No. 2 carburetors to 1.4 foot-pounds, using a foot-pound torque wrench. Turn the remote throttle stop screw clockwise to return the remote throttle stop screw and the throttle lever to their original positions.

    • 4

      Launch the WaveRunner and start its engine. Let the engine warm up for three to five minutes until it reaches its normal operating temperature. Move the WaveRunner's throttle to the "Trolling Speed" setting. Verify the engine's speed, using the tachometer.

    • 5

      Turn the remote throttle stop screw -- clockwise to increase the engine speed or counterclockwise to reduce the engine's speed -- using your hand or a flat-head screwdriver, until it is within 50 rpm of 1,350 rpm.

    • 6

      Remove the lock plate and lanyard from the kill switch and replace the seat.