Strange Idle Mercruiser 8.1S

[RichardS]

Hi Everyone,<br /><br />I am running 2 Merc 8.1s engines in a 41 ft Trojan Express. Both engines idle fine in neutral but if you apply power to the starbord engine and then back the trottle down quickly, the engine rpm drops to almost nothing and then recovers back to where it was before you bumped it. When manuvering the boat at 650 to 750 rpm, I run the risk of loosing the engine because of this.<br />I had the Mercruiser boys come out and they ran a diagnostic on the engine and everything checked out ok.<br /><br />Any input would be greatly appreciated.<br />Richard

 

[rodbolt]

Re: Strange Idle Mercruiser 8.1S

next time tell them to watch the TPS and the IAC readings. if nothing shows up as a fault code then you have what we call an "in range failure" now is when experience with EFI and how it all works together as well as how to interpet the huge amount of data that is avalible.<br /> good luck and post us what they recorded on the laptop