Maximum speed is set at the factory and should not be altered. Like idle speed, maximum speed is controlled by the amount of fuel injected. This adjustment requires special equipment. Figure 323 shows where the adjustment is made. The bolt is secured with a lock nut. If you have experience with fuel-injected engines, you can temporarily adjust the bolt to start the engine for a trip to the nearest service station.
Fig. 323. Location of the maximum speed adjusting bolt. Use two wrenches to loosen or tighten the lock nut