Mercury exhaust screw problems???

[BoneDigger]

A friend of mine has a 2000 model mercury 125 HP (Tracker model) that recently blew a cylinder even though all seemed to be working right with the motor (oil pump, etc.). When he took it to the mechanic he was told that he (mechanic) had seen this happen several times before and that the problem was improperly torqued exhaust screws. He said it is a factory defect/problem and that they should be torqued at 18 fp but are only registering 12 fp. He said this lets moisture in and can cause damage or a blown cylinder. Does this sound right? I have a 90 HP Mercury of the same year and wonder if I need to have this checked. Any ideas?<br /><br />Todd in TX

 

[dilligafda]

Re: Mercury exhaust screw problems???

"He said it is a factory defect/problem and that they should be torqued at 18 fp but are only registering 12 fp."<br /><br />Not likely a factory defect. Considering that the bolts are subjected to a constant heating and cooling cycles, it's not suprizing to me that they were a few lb.ft. off of factory spec. It's the same heating and cooling that requires some bolts to be retorqued after an engine has been run through a few cycles.<br /><br />With that being said, I don't recall seeing a 125 (or any other engine)fail for that reason alone. One thing I have seen is a cylinder not firing causing water to enter the cylinder through the exhaust and scoring the cylinder. Have your friends technician check the ignition system over.<br /><br />Good luck and keep us posted!