i have a 18 foot pontoon boat that has a 2000 40 hp mercury bigfoot on it.i came across a deal for a boat, trailer, and a 89 mercury 850 for 500 dollars i only want motor .does anyone now about this motor? the guy says it run great that i can hear it run on boat the only reason getting ride of it so cheap is he is in need a cash fast .what do you guys think? should i check it out? do you know how long the shaft needs to be to work on a pontoon? dont know much about boats or motors just wanted something bigger than a 40 hp on my toon.thanks for any help you could give a newbie to boating. also it doesnt have power trim or tilt but my 40 does can i use the power trim on the 850?what about controls?