The next MGP practice session is on Wednesday (1800 BST)
The weather-delayed Manx Grand Prix got under way on Tuesday night as riders at last negotiated the 37.73 mile course.
But conditions were still hazardous, with spillages on the roads plus fog meaning a speed-controlled lap.
Newcomers were restricted to one lap only, accompanied by travelling marshals.
A landslip at Ballig had resulted in a muddy road surface and spilled diesel was discovered at various point of the course.
The MGP is due to finish on 29 August.