Sluggish Merc 2007 40Hp 4 stroke/4 cyl Big Foot

[Gouda]

I have had this since new and it may have 100 hours on it. It is acting odd. It is very sluggish and does not seem to have any power. It starts right up and runs ok up to about 2400 RPM them it seems to lose power. It will not go over 3200 RPM. It does not quit ever, but acts like it is running on 2 cylinders. I replaced the plugs and that did not help. Any suggestions on what to check? Any help would be appreciated. All normal maintenance is up to date.

Thanks

 

[RadarJet]

I would start with the basics first. Are you running new fuel, is the vent open, and fuel line not pinched anywhere? Is the air intake clogged or blocked? I would also pull the cover off and see if the coil and rectifier are in good shape and not melted/ burned. Check the wire connections too near those. Is it pumping water and no alarms going off?

 

[Gouda]

opps

 

[Gouda]

No audible signal, fuel only a couple days old, It pumps water out as it should. I did not notice any thing out of the ordinary with the cover off, but will check again. Tank vent was open. Fuel line appears fine, not pinched.

 

[RadarJet]

This is an EFI motor, not carbureted, right? I have a 2002 60 hp efi jet that completely melted the coils a few years back. I would use a spark tester on all plugs just to check. The other things I could think of checking are the fuel filters and the fuel pump to make sure they are clean & unblocked. Run some concentrated Seafoam through it next time too. Sucks you are having this problem.

 

[Gouda]

Yes, EFI. Checking the plugs and fuel system today. I have noticed something else that is curious. The last 30-40% of the throttle throw does nothing to increase rpm. Could something in the linkage have slipped or become disconnected causing that? I never have thought it was right, but this problem caused me to think a bit more.

 

[Gouda]

any other ideas?