I think they're geared lower as well, for fitting bigger, flatter props. Good for pushing big things slowly (or towing sailing dinghies). Heavy, though — I used to have to stand with both feet on the transom to tilt our 25hp four-stroke Bigfoot.
Aha, geared lower sounds right, I assume one could put a bigger pitched prop on if it was to go onto a smaller/lighter boat?
Our 16ft sports dory has a 1996 90hp 2st ELPT & I think its a bigfoot (maybe) anyway it gets to 40mph in an instant & but no more. Its pretty lively with a full throttle start!
Was thinking of sticking it on our new purchase a Quicksilver 485 which weighs about 400kg less than the current 1100kg boat.
I'd expect it to need something coarser pitched. Our Avon SR4's Bigfoot 25 was replaced by a 40hp two-stroke off a Ribcraft 4.8 without changing the prop. It took off like a scalded cat and hit the rev limiter with the throttle three quarters open. Very good for getting in through the surf, but really it did need quite lot more pitch.
I think the weight ratio between the SR4 and the Ribcraft is probably about the same as in your case, so you might have a similar experience.
The 90hp gearbox is the same as a bigfoot, so on your engine you wont have the choice of a bigfoot. The 50/60 bigfoot uses the 75/90/115 gearbox the same gearbox as as yours. Long shaft only option. Gear ratio is 2.31:1 rather than the standard ratio of 1.64:1 (on the 50/60hp) If any of that makes sense!!
