Alright, My 2008 Etec 150 HO (E150DHLSCR) has been running like a top all spring. I took her out today, and all normal for most of the day. First crank start, smooth idle, smooth acceleration, smooth run at top-end spot to spot with some fishing time at each. Always started and ran smooth each time.
Later in the day, was making a run for several miles to get to a bay I wanted to fish, and had a hiccup with throttle wide open. RPMs were running at 5000, then dipped to 4900 for a moment, then back to normal. Ran normal the rest of the few miles, and didn't think much of it.
Fished for a while and decided to make the long run back towards the launch (about 20 miles). In that 20 miles, the hiccups of temporary loss of RPMs down from 5000 to 4900 or 4800 happened more frequently.. Probably a total of 12 times in that 20 miles. Each time bogged down for a few seconds, but came back to normal. When I got closer to the ramp, I worked it through all ranges from idle to WOT. Idle still nice and smooth. Smooth and normal acceleration to plane, and smooth transition to top-end RPMs. But still had a couple more hiccups before the ramp while opened up.
History on the motor.. I'm second owner and purchased 4.5 years ago with about 25 hours on it. The first owner did not use it much, obviously, and it spent a lot of storage time in his garage before I bought it. Only major issue I've had is an injector went out shortly after purchasing when I had the motor up around 40 hours. I attributed that to extended storage gumming that injector and made the painful decision to replace all 6 injectors at that time expecting the others were probably in the same condition. Since then, the engine has been great to me, and I use it a lot in the summers, keep it maintained, garage kept, winterized in winter, and have only run ethanol-free premium fuel for the 4.5 years I've owned it. The motor currently has 78 hours on it.
This model has the inline disposable fuel filter that I'm going to replace first in hopes it might be dirty enough to have restricted fuel flow at the top end on those long runs, but I'm guessing that might not be the issue... as much as I hope it is... I can see some particulates caught in the folds of the filter, so maybe I'll be that lucky...
I'm reaching out to see if folks have dealt with this, and would love to hear advise on some likely culprits.
Thanks in advance!