Knot Today
New member
Hello all, been having issues with these pumps. Little back ground first. Merc 260 in 85 Sundancer 260. New engine around 80 hours ago (2 years). New Sierra mechanical pump put on with new engine. Lost pressure, sent out for warrenty. Put known good used pump on while i wait for warrenty. Used pump went bad, lost pressure. Installed new pump late last season. Start this season doing some testing Ignition advance issues. Should mention I have fuel pressure gauge inline to carb. While testing seen gauge at 12psi @4000rpm. Fuel spraying out Venturi once secondary opened. So, went to Mercruiser dealer bought new OEM pump, that should do it right? Have 14hrs on this pump and lost high rpm. Idle at 3.5psi and build to 5. WOT for 30 seconds or so, starts dieing off, check gauge, @ 1psi? Inspected fuel tank again, clean as a whistle, pickup tube clean, fuel lines new, pre-sediment filter glass good. Took spin on filter off, poured into glass jar, clean fuel and no water. Put new filter on just because. Idles now @ 3.5psi. What is going on? Why would I be going through so many pumps?