2006 mercury 40hp 4 stoke efi Big Foot ser#1B315603 (surging & running rich)

[tim88]

I have just purchased this motor but it has 2 issues I hope someone can help me with. It starts fine but it surges while idling and when you rev it, It doesnt seem to go away while giving it the gas. and its all so is running rich. I thought surging was a lean fuel problem but Im having a rich fuel problem and surging. could anyone help Im lost on this. Thanks in advance for any help.

[EuropeanAM]

Need to check fuel pressure and determine if it is remaining constant or changing.

Also need someone with the CDS (Computer Diagnostic System) to monitor TPS, IAC and IAC Duty Cycle as there may be a problem with the idle position of the TPS.