The clearance is approximately 1/32 of an inch (.03125). There is some off center between impeller and liner due to manufacturing tolerances so check at the closest point. Less than 1/32 of an inch is ok if the impeller does not rub. More clearance than 1/32 of an inch will drop pressure and performance.
Archives
4. Can we change jet impeller pitch for load or speed?-
No. Unlike a propeller drive, a jet can develop full HP at a standstill. We choose an impeller that gives rated factory RPM at full throttle. RPM hardly varies between a heavy load and running fast with a light load.
3. How about a heavy load?-
A heavily loaded prop boat using a low pitch prop can haul much more weight than we can.
2. What speed will I get?-
It depends on the boat and the weight. A good setup will get about 80% of propeller speeds when using mid range prop pitch. A light weight prop boat using a high pitch prop can run twice our outboardjet speed.