I'm having issues with my '06 Sanger V210 that I picked up this spring. The thing runs great for about an hour and normally idles at 6-700 rpms, but after that it starts to idle at about 400 rpms. When this is happening the engine has trouble staying running and is hard to start after it dies (it runs completely normal at anything faster than idle speed). It idles so slow that the instruments lose power and start to jump around. I know it isn't a fuel issue (non oxygenated gas, fuel filter has been changed), and the corroded distributor cap and rotor have been replaced.
What really stumps me is why it only happens when the boat has been running for a while. Anybody have an idea of where to start with this? I was thinking about replacing the throttle position sensor, but don't want to throw money at it unless I am confident of the solution. Thanks for the help.