Re: 1954 Evinrude 7.5hp increase power?

[chinewalker]

Skip the modifications. Find a bigger motor. A 10 or 15 will do the trick without risk of stressing the motor. Those 7.5s have a nasty habit of ventilating the crankcase if you push them hard (or skimp on oil). A 10hp of similar vintage should not be hard to find…