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These tuning instructions apply to all of our units sold since October 2005. It can be used for all of our converted and non converted old units currently on closeout pricing. 

If your Adjust-A-Thrust isn't working, you don't have it tuned properly. Please follow the tuning instructions. It has taken us seven years to design not only the final model of the AAT, but the design of the unit involved the tuning of the thing as well. This is actually the 4th revision of the tuning instructions. Please read and understand them, if you have any questions concerning your AAT, don't hesitate to contact us  

We can figure it out if you cant!

UPDATED TUNING SHEET  2006 big bore revision

WARNING: DO NOT ATTEMPT TO ADJUST THE UNIT WHILE YOUR PWC IS RUNNING. SHUT OFF ENGINE, AND DISCONNECT SAFETY LANYARD WHEN MAKING ADJUSTMENTS.

*Before tuning the Adjust-A-Thrust, your craft should be in good running order and properly dialed in. If you are installing the Adjust-A-Thrust as part of a performance package and have made other modifications to your motor it is recommended that you dial in your craft with just the stock tailcone installed. The Adjust-A-Thrust can put a load on your motor similar to installing a bigger impeller and can make it hard to dial in your carbs.

 TUNING THE ADJUST-A-THRUST
*Remove shuttle, ride craft for 5 to 10 minutes until the motor is thoroughly warmed up. Make a full throttle run across the lake and note MAX RPM
*Install the shortest shuttle and the short bolt assy and ride again, note MAX RPM. NOTE Using the short bolt requires quite a bit of effort to install as the spring is being compressed more.
*If you don’t lose any RPM, install a longer shuttle and ride again.
*Keep trying longer shuttles until you start losing too much rpm, or stop gaining top speed
*If you are not losing RPM with the longest shuttle, you can install the long bolt assy. This increases the amount of shuttle travel, and decreases spring preload, speeding up the shift. When installing the long bolt assy, it is recommended that you go down 2 shuttle sizes and resume RPM tuning with the long bolt. You can also use the extra tuning washers to preload the spring with either bolt.
*Whichever bolt you end up using for your application, you MUST use the shuttle stop. It is there to prevent coil binding in the spring. When adding tuning washers, place them above the shuttle stop on the bolt. Adding washers increases the spring rate, which slows down the shift. It also decreases the total shift length of the shuttle.
*If you lose more than 150 rpm and the craft feels sluggish in the mid range and low end, the shuttle is too long. Holding machine at WOT for too long may cause engine seizure.
*Best speed is usually found 20 to 70 RPM below MAX RPM.
*4 stroke engines may not lose any rpm, but if you install too long of a shuttle, then you will lose top speed. Low end and midrange will be sluggish
*It should be noted that some machines are very sensitive to nozzle size and motor loading, If you lose to much RPM you are overloading the motor, and may seize your engine
*If you can’t get the unit dialed in with the shuttles that came in your kit, contact Wet Wolf Technologies, and we will set you up with different length shuttles.
* The Adjust-A-Thrust loads the motor similar to installing a bigger prop. Carbs may have to be adjusted.
*After riding in salt water unit should be flushed. This is can be done during normal flushing, just make sure to spray fresh water into the back of the pump.
*When installing the shuttle bolt, turn it in until it bottoms, then tweak the allen wrench about 3/16 of a turn, this will snug it up enough so that it wont fall out, but not enough to break off the threads.
* The screen provided over the inlet orifice is held in with a small amount of superglue. If the screen gets plugged, it will flush itself clean when the shuttle backshifts. If the screen becomes clogged and will not clean itself, it may be removed and the unit will function normally without the screen. 

  TUNING VARIABLES

BACKSHIFT
*Letting off the gas lowers pressure in the pump and lets the unit backshift into low gear, getting on the gas makes it upshift again. The more preload on the spring, the faster the unit backshifts.
SHUTTLE LENGTH
The Adjust-A-Thrust is shipped with 4 different length shuttles. These shuttles are matched to the particular pump that they are to be installed on. However, there are so many variables that affect pump performance, that your particular set-up may require different length shuttles. We stock shuttles from 2.0” to 4”  in ¼ “ increments.
*Whenever trying different shuttle lengths, always use the RPM drop method. If the motor won't lose RPM, install a longer shuttle and try again.
*If you can’t get the unit dialed in with the shuttles that came in your kit, contact Wet Wolf at (509) 280-5444, and we will send you different shuttles.
NOZZLE SIZE
The size of the exit nozzle is one of the factors that determines a crafts top speed., and how fast it gets there. The larger the exit nozzle is, the greater the increase in low end thrust. If you have an adjustable nozzle, you may want to install a slightly larger ring. (1 - 2MM larger) High horsepower machines (4 Strokes may wish to do some on water testing before boring the nozzle.
IMPELLERS
If you own a selection of impellers, installing a lighter pitched impeller will allow the engine to rev faster and increase your low end performance, while maintaining or increasing top speed
ALTITUDE
Changes in altitude affect the performance of your PWC. You may have to adjust carb settings when you change altitude. The Adjust-A-Thrust should also be adjusted when you change altitude. The higher you go, the less shift your motor can pull. Adjust the unit with the RPM drop method whenever you change altitude to get the most out of your craft.
ENGINE
Many PWC owners are constantly modifying their craft. As you increase engine horsepower, the unit may be adjusted for more shift as your engine can pull it.
TYPICAL TUNING SCENARIO:
Modified GTX LTD with skat trak magnum pump with 84mm nozzle ring installed, goes about 65mph on top end, with good acceleration, max RPM - 7300. After installing an 87mm nozzle ring and the Adjust-A-Thrust main body with no shuttles installed, max RPM went up to 7350, acceleration greatly improved, but top speed was down 2.5 to 3 mph. After installing the proper shuttle and tuning the Adjust-A-Thrust, max RPM came down to 7260, top speed increased to 66 mph, and there was no loss of that killer bottom end gained by enlarging the exit nozzle.

*If you bore the exit nozzle, you should check the size of  the steering nozzle. Generally, the steering nozzle should be 2 – 3 mm larger than the exit nozzle. If you do not bore the steering nozzle, thrust centering of the handlebars will be more noticeable, and it will make it harder to turn at full throttle.

  NOTE For twin engine jet boats, the additional tuning washers may be used in one unit to even out RPM between the 2 engines at WOT

Questions or comments, call Wet Wolf Technologies (509) 280-5444 or e-mail brucew@wetwolf.com

UPDATED TUNING SHEET   2006 big shuttle revision