All... I recently bought a "fixer upper" Ranger 518 VX bass boat with a 1999 200 Optimax on it. The motor would not start, or run initially so I bought a maintenance manual, and went to work :). After replacing the low/high pressure fuel pumps, rebuilding the diaphragm fuel pump, replacing a coil, the spark plugs, and a few fuel lines, I have it running pretty well. However, there are three specific issues I'm struggling to resolve.
The first issue is that at WOT I can only turn a standard 25P prop about 5400 rpms, but the boat does run 69 mph (GPS) while at that range. It's just that everyone is telling me this boat/motor combo should be turning the prop at the upper end of the rpms, which is 5750, and I don't want to leave anything on the table :).
The second issue is that the motor surges some when switching between neutral, forward, and reverse. An example is when I get up around a dock trying to park it. When shifting quickly between the gears, the motor rpm's will run up/down for just a couple of seconds before settling down (like it is doesn't know where to stabilize???).
The third issue is that when I take off, I get a hesitation, but not like a stumble or it's stuttering. It's just like I pressed the hot foot down, and the motor doesn't react for a second, or so??? Once it revs though, it puts the boat on plane very well, and runs nicely after that.
Other than these things, I'm very happy with this motor. Can anyone shed any light on some things that could cause these symptoms? Thank you.
1. Engine Serial Number 0G886121
2. Year/Make/Model 1999 / Merc / 200 Opti
3. Prop you are Running 25P Tempest
4. Current Maximum RPM 5400 RPM
5. Idle and WOT Water Pressure Readings 650 rpm @ idle / 23 PSI WOT water pressure
6. Smart-craft or Analog Instruments? Analog