Re: 1985 25/20hp rude powerhead swap
Hi Goldfish,<br /> It's not just the exhaust making the 10hp difference. It's the carb, intake, etc. All, combined, make up the difference. <br /> As for why they didn't use the through-hub on the 25, I think part of it was economics. The non-hubbed exhaust unit was tried and true (very similar to the older 22-cuber lowers), props were available at the 25hp level (different hub, but blade designs were around), and it made for a good price point motor between the 15hp and 35hp. The through-hub unit was a new design and probably cost much more to build.<br /> I'm thinking out loud and hypothetically here, but if the 1981 15hp cost $900 and the 1981 35hp cost $2000, it wouldn't make much sense to offer an essentially the same 25hp for $1800 or so, making a huge gap between offered models. But, with a less deluxe offering at 25hp, maybe the cost comes down to $1400 or so, making the gap much less imposing. A few years go by, the tooling cost of the 35hp unit is paid for, props are available in many sizes, and they drop the old design unit in favor of the through-hub unit for all 31.8 cubers, adding a 20hp model. <br /> As a footnote, the non-through hub unit stuck around for a few more years, being used in the base model 28SPL motors in the late 1980s.<br />- Scott
