Boat rudders may be either outboard or inboard. Both inboard and outboard engines are used. Johnson Outboards was a US based manufacturer of outboard motors. Vedeneyev M-14V-26 radial engines mounted in outboard nacelles. Trolling motors calibrate speed more accurately than large outboard motors. V6 engines are popular powerplants in medium to large outboard motors. The purchase included 300 defective outboard motors. On boats, cowlings are a cover for an outboard motor. Pump-jet propulsion is available as an option on most outboard motors. The original engine nacelles incorporated thrust reversers taken from the 727 outboard nacelles. Such valves are widely used in motorcycle, ATV, and marine outboard engines. OMC sold 100,000 motors in 2000 and had one third of the outboard market. Yanmar of Japan produced some small, charge-cooled rotory engines for chainsaws and outboard engines. Electrical power is primarily provided by generators located on each of the outboard engines. Mixed on Mackie 32x8 with no compressors or outboard eq.