Have a 84 model 17ft Bass Tracker Mercury 50. Water was in the gas according to local marine shop, wouldn't maintain a idle and hard to start. $520 later for a complete carburetor rebuild I took it out to the lake and it was still hard to start. Take it back to the marina, guy pops the top and says aha yes you had a fuel line getting pinched you should be fine. Take it BACK out to the lake, starts right up, idles great, I'm thinking good the problem is fixed. I ease into it and at full throttle I'm going about 1/4 speed. Will build to higher rpm's in neutral but not in gear. My dad looked at the linkage and says it all looks good to him. So here I am about to take this thing to the shop for the 3rd time. I'm telling them I'm leaving it this time until it's fixed as it should be. I think it's rediculous I payed $520 and still have a boat that takes an hour to get across a small lake. Does anyone have any ideas or tips? Things I should say to the shop? Boat starts right up, maintains idle, runs very smooth, does not miss, but at full throttle it's simply not even reaching half speed or rpm's. Any info is greatly appreciated.