Mercury 115 - flat on it's face

[Bill Collector]

I have a 1987 Merc 115 in line 6. I've had it one month. First weekend I filled the boat up with super and drove it for about two hours and cleaned it out good. Boat ran great. Next weekend, same thing. This past weekend i went to accelerate and it won't get over a quarter throttle. I replaced the fuel line/bulb and rebuilt the fuel pump. Took it out yesterday and same deal. I sprayed the Mercury engine tune in the carbs while it was running and when I hit the middle carb the engine would die. The top and bottom carb nothing would happen. I also squeezed the bulb while we were moving and there was no change what-so-ever. The engine would surge a bit on it's own ever so slightly and it sounded to me like it was all of a sudden going to give way and take off.

I'm buying a manual today and checking compression. I have no idea what direction to go in so I'm starting with rebuilding the carbs. Boat starts up and idles fine, just won't accelerate at all. I can get it up on plane but there's no power at all out of the hole. It has champion plugs in it. Not sure if that's the right plug either.
THanks in advance! I need all the help I can get.

Oh and I also took it to the dealer to have the lower unit installed which he did for $259.

 

[Chris1956]

Re: Mercury 115 - flat on it's face

Bill, After the compression check check for spark on all cylinders. If it is getting spark on all six, the carbs are the next choice.

Check the bottom spark plug for water droplets. Plugs are likely gapless Champion L76V or L78V. NGK makes a corresponding plug as well. (BUHW or BUHW2)