[mbuhler]

I recently purchased a 24 ft triple pontoon with a 2005 Mercury 115, 4-stroke. The first few times I took it out on the water, it ran great. Max speed was about 27 mph, can't remember exactly, but over 5000 rpms. Now I am only able to go max 20 mph at about 4500 rpm and it begins to miss. The problem seems to be getting worse. I changed the fuel filter, but that is all I have done. Does anyone have any suggestions for what may be causing the missing at higher rpms? (It does not begin to miss until it is about 4500 rpm's).

[raymor]

When you say you changed the fuel filter was this an external or the one on the motor. I was told not to run my 115 hp 4-stroke without an external 10 micron fuel filter. I use the Yamaha one and change it every season. I have the same year motor as you do and the power head is made by Yamaha.