have a 1979 115mercury outbord going at full speed lose power but doesnt die will start and run still .any sug

Answer 1

definitely sounds like your fulel filters are clogged up, change all of them.

also check and see to make sure your fuel tank is not full of deposits or rust at the suction hole, this might also prevent it from running smooth.

basically at full throttle there is high fuel flow through the lines, causing any debree to rise and plug up any holes slowly (as debree builds, from the bottom of your fuel tank or the bottom of your fuel filters) and cloggs the lines, so the result is you loosing power slowly as the lines clog more and more. Then when you shut it down or cut power significantly, the debree falls back down to the bottom of the fuel tank or fuel filters, thus allowing fuel to flow freely again.

this is very common in older boats.

good luck.

Answer 2

I have a 1968 Mercury that pretty much does the same thing. After I run full speed and kill the motor it won't start back up. I believe I am having fuel problems and I am going to take it to get it serviced, I will let you know what I find out.

Sounds like you might need to check your fuel lines, they often get sludge buildup which blocks good fuel flow....faster speeds need more fuel.