Pulsing idle when cold

[scoflaw]

Have a pair of twin 5.0's MPI 2006, thats just about to come off of warranty. The colder the temp has become, the more these motors will pulse at an idle. Once warmed up they run fine. They just don't have a cold fast idle. Merc tech says the IAC checks out fine on his scanner. He says he would like to see them idle higher, but doesn't have an answer. Any ideas?

 

[Pete104]

Re: Pulsing idle when cold

Easiest thing to do is get a 6 gallon can. 5 gallons of premium gas, a container of Mercury fuel system cleaner. Dump that in the remote tank. New water seperator filter for each engine.
Replace both filters. Run the fresh fuel mix thru each engine. It should help clean injectors, rails etc.

 

[Don S]

Re: Pulsing idle when cold

Sounds to me like your "Merc Tech" isn't much of one. There are a lot of things (including dirty fuel injectors) that can cause the problem you have. Vacuum leaks, corroded electrical terminal, low compression.
Here is a link to the manual on your engine.
http://www.4shared.com/document/FWwx1Vs7/Service_Manual_36_Rev_1_SBC.html