Re: Help, New Motor is much slower!
After reading through this thread, I was thinking the same thing. There's no way to mount a 15" shaft motor 6" low unless they cut off the top brackets. ( I had to mention this because I've seen it done, on brand new motors).
I had a guy here the other day with a brand new Mercury 15hp on a 15' tinny, the dealer that sold him the motor for his 20" transom boat sold him a 15" shaft motor. Since the 15hp is a clamp on only motor, they took a saw and cut a 5" notch in his transom, smeared the whole area with 5200 sealer, then cut two huge chunks out of the splashwell to allow the clamps to drop through the pan.
They then took the fuel hose from the new motor and cut the end, installing it between an existing fuel filter and the motor. They left the old primer bulb between the tank and filter, and another right at the tank, a 6 gallon portable at the front of the boat.
Both old primer bulbs were leaking, the fuel hoses in the boat were rotted, and the motor was now mounted too low, with the AV plate below the bottom by an inch. The boat did no more than 12 mph, with 6 gallon of gas and myself in an empty hull.
I raised the motor for a test run, it gained 9 mph just by getting the AV plate above the bottom of the boat. I swapped the prop for a lower pitch, and gained 2 more mph. He was happy with running 22-23 mph in that boat. He's bringing it back so I can fix the splashwell, transom, and install a proper transom bracket to mount the motor properly. We'll deal with maybe better matching the prop after the motor is mounted properly since the set back created by a transom bracket may again change the required prop size and pitch. So much for the dealer's free installation. Someone needs to take away their Sawzall and tin snips.
