2013 60hp 4 stroke mercury efi misses at high rpm

[miichaeI]

I have a 2013 60hp efi 4 stroke I bought brand new. Hasn't gave me a problem at all till now. When I'm running 4800rpm or less the motor runs perfect. At 5000 and higher it has a intermediate miss dropping rpms as it misses. It will run good then miss and run good then miss only 5000 rpm or above. Here what I have done so far.

1. Drained fuel tank and put fresh gas.
2. Drained vst tank and checked screen on pump which was clean. The vst looked new inside
3. new spark plugs.
4. New fuel filter.

Still missing at 5k rpm or over. If I keep it at 4500-4800 rpm it runs perfect. Any other ideas?

 

[miichaeI]

Think its electrical or fuel related?

 

[Kronos]

Have you checked if there is anything else that could be blocked between the tank and the injectors? Like an anti-siphon valve or what its called in english?

Could perhaps vacuum be building up in the tank? check if it's venting properly.

 

[Tuckertoon]

I've been experiencing the same for a couple of years. I haven't been able to find the answer. I've done all of the same things you mention. I did have some water in the fuel tank one year, I think from a marina. I installed a water separator but still get the problem and I pumped some gas off the bottom of the tank and let it sit overnight to look for separation and, I'm happy there is none, so no water at this time. This year, I replaced the fuel pump and all fuel hoses. There was a small amount of black sediment in the old pump. I've read that the hoses de laminate. I'll be launching the boat soon and report back.

 

[QBhoy]

I’d be tempted to run it off a smaller remote outboard tank, if you are currently running off a large built in tank now. Just to totally rule any pick up or water contamination...despite cleaning it out previously as you said. Like I say. Just to rule it out.
Other thing in my head is that there is a small chance your tacho is reading lower than it should and you are on the rpm limiter perhaps ? Have you changed the prop recently ? Likely not the issue but it came to mind.