1986 Seaswirl 17' with OMC 3.0L

by ROb
(Tucson,az)

I recently bought a 1986 Seaswirl 17' with the OMC 3.0L with a two year old rebuilt motor. I've taken it to the lake twice now, but it is not running correctly. The first time I took it, the highest rpms I could achieve was 3400 at 32mph(via GPS). The max operating range for the motor is 4200-4600 rpms. The boat was very slow to plane, taking a minute or more to do so, and not even able to plane with more than three people on board. When I got back from the lake, I checked the prop size(13 1/4X17P), which appears to be correct although it does have a few small chips in the blades. I changed and gapped the plugs, changed the oil, checked the points and cleaned the carb. I checked TDC, so I know the mark is correct on the crank. I then checked the timing, only to find it set at 30 degrees above TDC when it is supposed to be set between 1 and 4 degrees above TDC. I set the timing at 4 above TDC, and tuned the carb to idle at 550rpms. It was all set to factory specs. When I get to the lake the second time, the boat wont even start until I advance the timing. Once I get it running, I can only get 2900 rpms out of it and it would only plane with one person on board. Does anyone know what is wrong with my boat? I don't know where to go from here.