[barnacle]

Going from a 17 to a 19 you should see about a 400 rpm loss. You speed will go up even with your RPMs comming down. When you prop a outboard it is very important that the engine can hit the proper RPM. If im not mistaken your engine is a 5500 rpm engine. YOu want to make sure it can hit 5500 rpm if it only hits say 5100 the engine will probley live but it very hard on the powerhead. If your shy a bit you can raise the engine up one hole on the transome to pick up some more rpms. Just be sure your water intakes do not get to high. When playing with engine hights its good to have a water pressure gauge installed to make sure the cooling system is ok at higher engine mounting. What rpms are you getting with the 17?