MODEL AQ, AQSHO SERIES
ASSEMBLY INSTRUCTIONS
YAMAHA 200-250 HP, V6, 2 STROKE, 3.1 L
200-250 HP, V6, 4 STROKE, 4.2 L
1
1. Place the engine on the transom of your boat so that it is mounted vertically, in the normal fashion. Remove the
bolts holding the gearbox to the exhaust housing and remove gearbox assembly.
2. Remove the water pump assembly from the propeller drive, including the lower stainless steel plate, dowel pins,
and impeller drive key.
3. Install the jet driveshaft assembly into the spiral pump housing locking it in place with the four 5/16-18 x 1
bolts with lock washers. Use grease on the threads. Tighten to 15 ft-lbs.
4. Install the water pump assembly on top of the 3/4 inch thick aluminum adapter and stainless steel plate. The
stainless steel plate design was changed recently. The front extends beyond the pump housing and interferes
with the adapter plate. Cut off the section that extends beyond the pump housing. Be sure also to install the
water pump impeller drive key removed from the propeller drive. Lock in place using four 5/16-18 x 2-1/2 bolts
and lockwashers. Grease the threads. Tighten to 10 ft-lbs.
The tapered thrust ring assembly above the water
pump on the propeller drive is not used on the jet drive.
5. The large 3/4 inch adapter plate is attached to the exhaust housing to hold the jet drive. A 1/4 x 2 inch plastic
shift rod guide in the front of the plate guides the disconnected shift rod. Two 8 x 12MM dowels locate the
plate, seven M10 x 34MM bolts with lock washers secure it. Grease the bolt threads and the end of the pin
where it slides in the shift rod. Tighten to 22 ft-lbs.
6. Next, attach the jet drive to the motor. Two 3/16 x 1/2 dowel pins center the jet drive on the adapter plate. Four
3/8-16 bolts from below and one 3/8-16 x 1-1/2 bolt from above rear with lockwashers are used. Select the
lower bolt lengths to suit the different counter bore depths so that all bolts enter the adapter plate the same
depth. The upper rear bolt is reached through the trim tab opening in the motor exhaust housing.
Grease the bolt threads, driveshaft spline generously, and rubber water tube pilot and guide the jet into place.
Tighten to 22 ft-lbs.
7. Next, install the impeller. Grease the shaft threads, key and impeller bore. Place the plastic sleeve inside the
impeller, hold the key in the nose of the impeller with your forefinger and slide onto the driveshaft. Install the
eight shim washers, and nut retainer on the shaft, up against the impeller, and bring the nut up snug by hand. Be
careful that the retainer does not fall into the thread groove and jam the nut.
Then bump the nut up snug with a wrench. If the ears of the retainer do not line up with the flats on the nut, spin
the nut off, turn the retainer over and tighten the nut again. In one of these two positions you will have
alignment and can fold the ears up against the nut to retain it. The flat in the retainer is angled to the ears to
allow this.
When, after use in sand and gravel, the blade clearance becomes more than about 1/32 inch between the
impeller edge and the water intake liner, one or more of the stainless shim washers can be transferred from the
bottom stack to the top of the impeller, which moves the impeller down into the tapered casing to reduce the
clearance.
Shims should not be used above the impeller on new installations, where no wear has occurred, unless the
blade clearance exceeds 1/32 inch. Insufficient blade clearance will do more harm than good from any
performance gains it might provide.
8. Place the intake casing in position with the lower end at the rear and tighten the six nuts. No lockwashers are
used. Grease the threads.
9. Attach the shift cable and cable anchor bracket to the jet drive.
