Optimax 150 High Revving at idle on startup
Here is the scenario.
Over the past few weeks, one of my 2 x 150 Optis has been high revving on startup and then dieing. A subsequent start would proceed with a regular startup and idle. This has been generally happening after a trip or at a cold start and not all the time. This morning, as I went to start the engine for the first time, it idled normally for a couple of seconds and then it surged without stopping, so much so that I had to switch the key ignition off. Any subsequent attempt to restart the engine produced an immediate surge and over revving that can be only stopped by switching the key off.
I did not have the DDT with me and I have been unable to check the parameters but I did a full check only last week and everything was fine with no errors. I have also tried adjusting the accelerator and gears a few times but it hasn't made any difference.
Can anyone shed some light on what could be wrong? The pulse fuel pump diaphragms were replaced only a few months ago`, so I would exclude this.
I look forward to some feedback.