I got a 50 hp Mariner tiller, I believe its a 1999. I've always winterized and stored it in the garage in winters and never had a problem. This year I had it out and it was running great like it always had. We were heading in when the motor just shut down, I mean it stopped so hard it threw my brother and I to the floor. We restarted the motor and we could put it in forward and it would work but as soon as I gave it any throttle it would start to shake and then shut down hard again. I drained to lower unit oil to see how bad the damage was and surprisingly it wasn't bad, so I refilled it and put the muffs on and it started fine, in neutral it will throttle it all the way open, so I put it in gear and throttled up and it got wide open without a problem. So I took it out to a small local lake and as soon as I started to throttled up it did it again. Does this sound like a blown lower unit or something else? My local boat shop says its 150$ just to look at it. Any input would be appreciated.