American Turbine SD203 Owner'S Manual Download Page 4

material, or assembly of an American Turbine, Inc. 
5. American Turbine, Inc. shall not be liable for any incidental, consequential or other damages whatsoever, including but not 
limited to: loss of use, loss of time, inconvenience, cost of returning the defective product to American Turbine, Inc., travel, 
lodging, or damage to personal property. 
6. Some states do not allow the exclusion or limitation of incidental or consequential damages, so the above limitations may 
not apply to you. 
7. This warranty is the only express warranty applicable to American Turbine, Inc. products, and is in lieu of any other express 
or implied warranties, including warranties of merchantability and fitness 
for a particular purpose. All implied warranties are limited in duration to minimum period required by State law. American Turbine, 
Inc. neither assumes or authorizes any other person to assume for it any other liability or warranty in connection with its 
products, 
8. Some states do not allow limitations on the duration of implied warranties, so the above limitations may not apply to you. 
9. This warranty gives you specific legal rights, and you may also have other rights which may vary state to state. 

 
 

UNDERSTANDING YOUR BOAT 

Most boat owners like to perform at least a certain amount of their boat maintenance themselves to ensure continuing good 
performance and reliability. 
To avoid unnecessary trips to the service center, it might be useful to have a checklist, which can be run through 
systematically, in the hope of pinpointing the problem quickly. The boat can be divided into three categories - jet unit, engine, 
and hull. 
If something is "wrong" with the boat it is usually poor acceleration and load carrying, coupled with excessive fuel 
consumption or engine RPM's. It could be unusual noise coming from the mechanicals, or possibly just poor top speed. All of 
these things may be present to some degree, but the usual complaint is that the boat is just plain "gutless". 

TACHOMETER 

The most important single instrument on the boat when considering performance drop-off is the engine tachometer. 
The great thing about jet boats is that the engine RPM's should remain the same throughout the life of the boat, regardless of 
age, loading, water conditions, towing, whatever. 
There is no situation where the RPM's should be different from when the boat was new, and as an owner, you will 
know what these are. At any time, you should be able to open the throttle fully and get exactly the same maximum reading you 
have been used to. Or perhaps you are finding it needs more RPM's to cruise your normal load? RPM's are a most important 
indicator of proper operation of the boat. 
It is important at this stage to feel confident that your tachometer is reading accurately. 
Now we come to our check list, and determination of which major area is the problem. The simplest way is a check 
on the RPM's first. They could be normal, high, or low, and this will pin point the place to look: 

 

A. Normal maximum RPM = hull problem. 

If the boat is performing poorly and the maximum RPM's are normal and what you are used to, you can look to the 
hull and some of the external parts. These include: 
1. 

Overload: 

Too much weight aboard. 

2. 

Balance: 

Either too much weight aft, which will cause the nose to be too high and make planing difficult, or if the weight is 

too far forward, it will cause the nose to plow, difficult steering, wetness, and poor top speed. 
3. 

Reverse bucket: 

Is the bucket dragging in the reverse stream? Make sure the control is fully up. 

4. 

Excessive hull drag: 

Is there some external hull obstruction such as rough surface, broken keel strips, or other reason impeding 

the smooth flow of water over the hull bottom? A visual check on the trailer should reveal if there is. Metal hulls can 
have a "hook" bashed into them forward of the transom which can cause the bow to plow. The planing surface forward of the 
transom six to nine feet should be true and flat. 

 
B. High rpm = jet unit problem. 

Higher than normal RPM's, lack of thrust, slipping clutch feel, engine racing and no go? 
1. 

Blockage: 

The most common problem is weeds and stones blocking the intake grate. Also be aware of ski rope, fishing line 

and plastic bags winding around the pump shaft. Small sticks and stones can become lodged in the impeller affecting the 
performance 
dramatically, objects trapped in the impeller can cause the rotating assembly to be out of balance, causing severe 
vibration. Make sure the water passage through the jet is clear. 
2. 

Impeller wear: 

The heart of the jet is the impeller, and its condition. If you run in shallow gravel beds or across sandbars the 

leading edges will become dull and inefficient. Pumping sand will increase the wear-ring to impeller clearance. Causing cavitations 
and loss of performance. 
3. 

Bowl / stator vanes: 

It's not too much of a problem, but the leading edge of the fixed stator vanes can become blunt and 

damaged. 
4. 

Air leaks: 

If excessive air leaks into the intake ahead of the impeller, the jet unit will "slip". Possible sources of air leaks are 

through a faulty gland seal, which is usually accompanied by a static water leak into the boat when standing idle. 
So if the gland is worn out and leaking into the boat with the engine off, it can also suck air when accelerating on to plane, and 
if this happens, then the thrust is reduced dramatically. Air can also be introduced into the system via the inspection cover, so 
you will want to make sure the cover is tight. 

 
C. Low RPM = engine problem 

There is generally no way the jet unit can overload the engine and bring the RPM's down. If the RPM's are down 
from usual, it is almost certain to be an engine problem. A compression check will usually reveal leaking piston rings or valves, 

Summary of Contents for SD203

Page 1: ...SD203 OWNER MANUAL SUPER DUTY JET 203mm Axial Flow THE POWER IS IN THE PUMP...

Page 2: ...ft Control With the control in full reverse the reverse bucket should completely cover the nozzle s discharge opening In full forward the reverse bucket should clear the entire nozzle discharge openin...

Page 3: ...LANOCOTE Also steering parts need to be cleaned and coated SAFETY 1 Retrieving Skiers We recommend shutting off the engine when retrieving downed skiers 2 Ski Ropes Ski ropes should be avoided if pos...

Page 4: ...come to our check list and determination of which major area is the problem The simplest way is a check on the RPM s first They could be normal high or low and this will pin point the place to look A...

Page 5: ...grumble at idle that increases with engine RPM s then it is likely to be a rough worn water damaged thrust bearing If water has gotten into the bearing it is usually as a result of a flooded bilge at...

Page 6: ...30 29 10 23 26 25 27 32 20 31 35 77 54 33 34 78 2 47 38 68 66 67 64 75 58 71 61 72 69 70 59 57 60 45 74 76 55 18 62 73 65 63 56 52 49 50 46 51 22 21 17 13 14 16 15 1 28 5 3 6 4 8 7 48 53 American Tur...

Page 7: ...4 ITEM DESCRIPTION PART QTY 40 5 16 18 LOCK NUT F05 18 LN 4 41 O RING INTAKE SD 312 O3901 1 42 5 16 18 X 1 HEX HEAD CAP SCREW F05 18 08 HH 2 43 5 16 FLAT WASHER F05 FW 10 44 5 16 18 X 1 1 4 HEX HEAD C...

Page 8: ...American Turbine SD203 INTAKE ADAPTER GREASE ZERK for THRUST BEARING MECHANICAL SEAL IMPELLER GREASE ZERK for STATOR BEARINGS NOZZLE INSERT ROCK GRATE...

Page 9: ...American Turbine SD203 BEARING HOUSING GREASE ZERK WEEP HOLE HAND HOLE COVER STEERING EXTENSION REVERSE BUCKET INTAKE ADAPTER SUCTION PIECE STATOR STEERING NOZZLE NOZZLE HOUSING...

Page 10: ...L STEERING FASTENERS SD203 SPECIFICATIONS wear ring 045 055 Clearance between impeller and IMPELLER WEAR RING SPECIFICATIONS Wear ring I D 8 005 8 000 Impeller O D 7 955 7 950 A FROM HUB DETAIL A MEAS...

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