Hello and good morning,<br /><br />I searched and found a lot of topics with RPMs and Probs, but maybe I got it wrong.<br /><br />If I take an engine, let's say like mine 1991 90HP Johnson, with the prop delivered by the shop (I think), there should be a difference in the RPM I can reach if I put this on a Jon boat or on a 24 pontoon (like mine). Or is that wrong ? <br /><br />I can reach just something above 4200 at full trottle. Does this mean I must use a smaller prop or one with "less pitch" to make my engine run faster ? I dont assume that would give me more speed, just more fuel usage ? Or what do I get wrong here ?<br /><br />Thanks for a clarification