I've got a 27ft Seasport, gas v-8 with power steering, Volvo outdrive, Yamaha 9.9 fourstroke and an Easy-Steer rod connecting the outdrive and the Yamaha. Works just fine with the main motor turned off. The marine power steering doesn't seem to be as stiff as an auto unit would be, even though they use the same pump. I do have hydraulic steering instead of cable, so that may make a difference.