RPM's dropping of 7.4L MPI

[gs65jgs]

I am experiencing a drop of RPM's on my port engine. If I run 3,000 - 3,200 rpm's it seems ok. This past weekend I had 8 adults and had to give it more
throttle to maintain plane. The rpm's started to drop off. Then it would surge to normal for a couple of minutes, only to drop off again. Any suggestions?

 

[The W.A.V.E.]

Water in the gas? Had this problem with one engine surging. Not sure if that was my problem however it cleared up with fresh gas and stabil.

 

[NJMatt50]

I just had this same problem, same boat. Put a gauge on the fuel rail and check your pressure. Should have 38#. Mine ended up being the fuel regulator down in the cooler box.