I have a 64 Johnson Seahorse 6hp, which i mounted on a 1964 12' Starcraft aluminum boat. The motor had not been run in 2 years. I changed the plugs, and put oil in the lower unit, as it was filled with rust colored greasy water. motor runs well, and will really crank up in neutral. But when in gear, under power, it will not plane the boat off. It seems like it just won't open up all the way. i would appreciate any advice.