I recently blew the lower unit on my 1988 johnson 140 looper so I replaced the lower unit with one from a 1986 johnson 110 crossflow. The lower unit fit like a glove and bolted right up. Gears are working fine and motor is running great. Problem is my speed. I understand the gear ratios are different in the lower units but 25% decrease in speed does make much sense. Anyhow I had a 19 pitch prop and I was only getting 5000rpm with the new lower unit and going 31mph. So I tried a 17 pitch and I am getting 5500rpm wide open trimmed up and only getting 32.5 mph. It used to go 46mph with the old lower unit with the 19 pitch. My concern is burning all this fuel with such little power with a big *** 500lb motor on a 17 foot boat only pushing 32mph. Doesnt make much sense to me. I can just get a 90hp and go 42mph. And I have a 140 and only go 32 mph???? Does this make sense?? Doesnt seem right to me and I'm goin to waste all this money on fuel and take an extra 10minutes to get to my honey hole. What should I do?? Do I have to live with this?? Is there a solution?? I was thinking about raising the motor on the transom to gain some mph. Thanks for any replies.
