I am having trouble getting the speed I think I should be getting out of my df 140 I recently installed. I had a 135 optimax on the boat and it would run about 52, now the suzuki only goes 42-43 tops. The motor has not had many hours on it. I was wondering what the problem is, if there is one at all. I thought I could get at least 48-49 out of it. I am wondering if could be something in the engine. I have a 19p powertech prop and it hits around 5600 rpm. I changed the spark plugs but did not Gap them before I put it on the boat(dont know if that is relavent). I dont have a jack plate so I dont know if it motor position related or not. I can say that there is a bad porpousing problem at anything over no trim and until i trim it all the way up at WOT til it starts to ventilate the prop and I mean it is waay up. Any suggestions would be greatly appreciated.
