I have a '95 BF50 that I change my own water pump on regularly. You need to remove the six bolts from the bottom that hold the lower unit on. Make sure you put loc-tite on before re-installing the bolts. The first time I took mine off,I removed threads with the bolts, and broe one bolt off. I dilled it perfect, and then broke off the EZ out bolt extractor...My frind is an aircraft metals tech journeyman, so he got the bolt out for me, and I further damaged the middle unit housing by incorrectly installing a new helicoil. It only cost me $382 for a new middle housig, $75 for a helcoil kit and a case of beer to get the broken bolt out. All in all...get the SEC LOC manual, and BE CAREFUL.
I LOVE my Honda, I've had it for 7 years now, use it several times a year and it always starts right up, uses very little gas and ges me to the fish!!
see this site http://sites.google.com/site/bf50impellernotes/
http://sites.google.com/site/bf50impellernotes/
First remove the three spark plugs, this will make spinning the engine easier. Next spin the fly wheel counter clockwise (in the direction of the arrow stamped on the fly wheel) until the cam shaft pulley timing mark matches up exactly with the notch on the engine block. You will have to look on top of the motor for the mark but it is stamped. Once the cam shaft is lined up remove the timing belt from the cam shaft pulley and turn the fly wheel counter clock wise until the timing notch stamped on the fly wheel are 2 teeth past the timing mark on the block (which is near the left most bolt on the engine hanging bracket). Slide the timing belt back over the cam shaft pulley, tighten the belt tensioner and spin the engine (counter clockwise) by hand a few revolution to make sure that the engine turns freely and valve stems are not hitting the cam shaft. If it turns freely with no issue put the plastic timing belt cover back on and try starting the motor up in water. Good luck!