I need some help. I have a 1997, 75 horsepower mercury on my pontoon boat. It's an oil injected 3 cylinder. It recently bogged and died while riding on the lake. The motor would crank but acted like it was starving for fuel and plugs were fouling. When at home and searching for the problem I found the main fuel line was busted, in the "Y" where the oil line connects. Replaced the line and plugs and it still ran extremely bad and would hardly idle. I decided to run a compression test and found the middle cylinder had no compression, zero, it will not even make the needle bounce. 120psi on the other two. Checked for a hole in the piston and found none, it's not blowing back out of the carburetor so I believe the reed valve is ok. I pulled the head plate and can't find any holes or cracks in the cylinder wall. Called a friend that is a professional boat mechanic, he came and checked it out and left scratching his head. No blowing or whistling sounds while turning over, no grinding or popping and no clue what's going on. I've seen pistons with holes build some compression. I appreciate any help.
