shawnfish » Today, 02:50[/url]"]the 20,s 25's and 30's if theyre built anything like the older ones they will all have the same powerhead and the same carb except the carb for each model (20,25 and 30) will have a restrictor in the carb throat to reduce the air going into the intakes making the difference in HP. the 35 will not have the restrictor in the carb throat. or..... its the manifolds that are different, if that's the case all 3 carb throats are the same and where the manifold bolts to the powerhead the intake holes are different diameters making the difference in hp. so you either have to swap the carbs or the intake manifold to get 5 more hp. but like I said im not sure about the post 1990 motors. but that's usually the case in the pre 1990 small outboards 40hp or less. look at a parts diagram for the 25 and 35 and you will know pretty quick. oh yeah one more thing, the newer models all have the same exhaust unlike the older models, some people say the different exhausts(thru and non thru hub) on the older ones hampered making a 25hp 35hp by swapping carbs/intakes and you didn't get every hp you should but its baloney.. the inner exhaust tubes were the same size and I know people on here (myself included) that went from 20 to 30hp or 25 to 35hp swapping carbs/intakes and they will all tell you that their motors have more noticeable hp... well built motors!
