04 subzuki 115 losing power at 4000 rpms

[mholzer]

I was wandering if you all could help me my Suzuki 115 4 stroke runs fine till you hit 4000 rpms then it acts like you pulled the throttle back. In a second or two it will take off again I changed the fuel water separator filter and the external fuel filter any ideas thanks

[Greg Moore]

You're probably on the right track with fuel. Most common fuel starves besides bad filters is plugged tank vent (run without fill cap to test), collapsed fuel lines (grey ones famous for this). Does the 04 run low and high pressure pumps? Don't know, but if it's like the newer motors, there is a low pressure pump that fills a mini float chamber on side of motor which houses the high pressure pump. This will be injected engines only. Poor flow due to anything I've mentioned or a failing low pressure pump or sticking float in that chamber will cause it to briefly act like it ran out of fuel until the float chamber catches back up.

[Hoosmatroos]

This is indeed a injection engine. In addition, there is a filter in the vapour separator tank (VST) that can be dirty. Part number: http://www.boats.net/parts/detail/su...642-90J00.html
But check the fuel lines and primer bulb as well. If the problem still persists then we have to look further.

[tnadeau]

Be sure you’re running the manufacturer’s recommended spark plugs and they are correctly gapped. Incorrect plugs can cause this too. If you haven’t changed them in awhile start there and perform a compression test while you have the plugs out. These things will check off a couple of boxes on the Outboard Troubleshooting List.