IJSBA is making this announcement regarding inquiry of a possible rule modification for Runabout Superstock.  IJSBA has been made aware of the need for rule clarifications and potential need for a safety intervention on Runabout Superstock watercraft.  Questions and comments on the rule inquiry will be accepted for 10 calendar days before IJSBA will make a final decision on this potential change.  Clarifications are effective immediately.  Questions or comments may be sent by email to info@ijsba.com.  Please see the rule inquiry and clarifications below.


IJSBA Rule RSS.4.7 Exhaust manifold, head pipe, expansion chamber, gaskets and hose between expansion chamber and waterbox may be modified/altered or aftermarket. Exhaust location of the exhaust gases may not be relocated. Original size opening must be maintained for exhaust exit. Waterbox may be
aftermarket or removed. No tuned portion of the exhaust shall protrude outside the hull. Through-hull exhaust outlet flap may be removed. Two Stroke and Four Stroke Runabout Limited classes: Removal of the plastic resonator is allowed. 

IJSBA is releasing an inquiry for public comment allowing the relocation of the exhaust exit for safety purposes.  On some modern personal watercraft, the exhaust gasses are discharged adjacent to the propulsion pump and steering components.  Aftermarket components allowed on Superstock Watercraft create much higher exhaust temperatures which could rapidly deteriorate the steering cables, couplers, and other components rising to safety issue potentially causing a steering failure.  IJSBA is considering updating this rule midseason to allow the relocation of exhaust gas discharge on Superstock watercraft to any area below the bondline on the aft section of the hull.



  1. Bulkhead Modification:


IJSBA Rule RSS.2.2 states: Hull and deck repairs may be made. However, these repairs must not alter the original configuration by more than 2.00mm (0.08 in.). Handles, drop-in type storage buckets, bolt-on type mirrors and gauges may be modified, aftermarket or removed provided a hazard is not created. Drop-in
type buckets are defined as being able to be removed without the use of any tool. Other than for the use of fasteners and the placement of allowable relocated parts  (i.e., Exhaust, ECU), the bulkhead may not be modified.   

IJSBA clarifies that this rule allows the cutting and modification of the bulkhead for the purpose of accommodating aftermarket exhaust and induction systems.  The bulkhead may be modified to the extent necessary to accommodate the allowed components.  Cuttings that were made for aftermarket exhaust and induction system do not need to be repaired.

       2.  ECU and Aftermarket Induction Systems:

IJSBA Rule RSS.8.2  states: original electronic control unit may be modified or aftermarket so long as it does not offer any additional inputs or outputs than the original unit, and it must connect with the original connections. No additional sensors may be added (e.g., exhaust gas temperature, detonation sensors, etc.). Engine temperature sensors may be disabled.  

IJSBA clarifies that, upon the installation of an aftermarket turbocharger system, the wastegate control of an aftermarket ECU will not be considered an additional output.  An electronic wastegate controller is common component of a turbocharger installation.  Because a separate electronic wastegate control is allowed under this rule, the wastegate being controlled by the aftermarket ECU is an allowable output because it is part of the legal control system.