The maximum speed is set at the factory and this adjustment should not be violated. Like idle speed, maximum speed is regulated by the amount of fuel injected. This adjustment requires special equipment. Figure 323 shows the location of the adjustment. The bolt is secured with a locknut. If you have experience working with injection engines, you can temporarily adjust the bolt to start the engine for a trip to the nearest service station.
Pic. 323. Location of the maximum speed adjusting bolt. Use two wrenches to loosen or tighten the locknut