i have a 1986 Mercruiser 170 and have had it out several times. most of the time it runs fine my dad and i did work to the cooling system and ignition system. pretty much completely replacing both systems. however. sometimes its rough to get going after shifting into forward or reverse the lower unit shifts and begins to accelerate and then falls on its face and dies like its run out of fuel all the sudden... shift back to neutral. restart the engine and usually it will take off and run fine. sometimes it takes multiple restarts but eventually it will take off.... ive replaced both fuel filters on the carb and the pump. with minimal if any improvement. has fresh gas. this boat set for several years before my dad and i got ahold of it. im not sure if the carb should be rebuilt of the fuel pump or both.... im a diesel engine guy.....