Just picked up a 14' flat bottom jon boat. It has a 83 Johnson 35hp that was tiller steer rope pull. Now it's either electric start or rope and has steering wheel. Steering works fine but question is about throttle. OK, The shift lever sits straight up when in neural as it should. I took it on the water the other day and when I moved lever/throttle forward it got to what is normally full throttle position and was just creeping along with the bow high. I thought it had clogged carb or something at first but I decided to shove the lever even further forward and down toward my feet and then it took off nicely and planed out at about 28-30mph. Why is the lever taking so long to engage the throttle on the engine? Any ideas