Hi everyone,
I have an '85 Alumacraft T-14XL 20" transom that I am working on. It is a project boat; I plan on adding decks and changing the layout a bit. To kick off the project I repowered the boat with a '16 E-Tec 30 w power trim and electric start. The original '85 30 (which I still have) is a low hour motor and runs flawlessly, but I wanted the convenience of power trim and the better fuel efficiency.
Being that the new motor is roughly 30 lbs heavier, I am having more problems with porpoising than ever. When I am alone in the boat, I must run the engine trimmed all the way in and there is still a good amount of bounce in the bow. Moving the fuel tank and battery forward has done almost nothing to help. When I have my two boys in the bow, it runs much better, however I still have to run with the trim close to being all the way in. Having to keep the engine tucked so far in wont let it reach the revs it should, thus killing top end and fuel economy.
I am going to upgrade to a stainless prop, and was thinking that a 4 blade prop might help lift the stern a bit and help the porpoising issue I'm having. If I were to go this route, should I drop 1" in pitch going from a 3 blade aluminum to a 4 blade stainless? My WOT rpm's are 5980-6000; right at max revs for this motor. That is lightly loaded and trimmed out about a third, but the porpoising causes the boat to be almost uncontrollable. The stock prop is a BRP 10.3x12x3. Do you think since my revs are so high that I should try a 10x12x4? Anyone have a similar setup with the same issues?
Thanks in advance for your input!
-Rob
I have an '85 Alumacraft T-14XL 20" transom that I am working on. It is a project boat; I plan on adding decks and changing the layout a bit. To kick off the project I repowered the boat with a '16 E-Tec 30 w power trim and electric start. The original '85 30 (which I still have) is a low hour motor and runs flawlessly, but I wanted the convenience of power trim and the better fuel efficiency.
Being that the new motor is roughly 30 lbs heavier, I am having more problems with porpoising than ever. When I am alone in the boat, I must run the engine trimmed all the way in and there is still a good amount of bounce in the bow. Moving the fuel tank and battery forward has done almost nothing to help. When I have my two boys in the bow, it runs much better, however I still have to run with the trim close to being all the way in. Having to keep the engine tucked so far in wont let it reach the revs it should, thus killing top end and fuel economy.
I am going to upgrade to a stainless prop, and was thinking that a 4 blade prop might help lift the stern a bit and help the porpoising issue I'm having. If I were to go this route, should I drop 1" in pitch going from a 3 blade aluminum to a 4 blade stainless? My WOT rpm's are 5980-6000; right at max revs for this motor. That is lightly loaded and trimmed out about a third, but the porpoising causes the boat to be almost uncontrollable. The stock prop is a BRP 10.3x12x3. Do you think since my revs are so high that I should try a 10x12x4? Anyone have a similar setup with the same issues?
Thanks in advance for your input!
-Rob