"John Dillard,
I have this
"John Dillard,
I have this same problem with a brand new 3.0 and I am finding it posted elsewhere. The problem seems to be in the the low rpm ciruit of the carb. It will Run fine when the throttle plate is open. It does not have to wide open, but 1500 rpm and up the engine has no hesition. The engine also starts when cold just fine. The problem by the way is not the temp, but that the pintle in the module is engaged (its supposed to be). However when it engages the engines stalls in low rpm (it aint supposed to). Part of the difficulty is that you can make the problem go away temporarily, but it comes back. Do not waste money replacing the module ($175.00) it won't change anything. The following worked temporarliy: fiddling with the idle needle, spraying Gum Out with a straw right down the pin holes on the venturi, rebuilding the carb. Rebuilding the carb gave me thrity hours of good performance, but the problem came back. No mechanic has been able to solve this and Mercruiser simply does not care once your check clears. I was considering buying a new carb, but I was afraid it might be a design defect common to all of the Mercarbs built for the new 3.0. Thats why I have been searching the web. I am sorry to say that I am becoming increasing convinced that it is a common problem caused by a flaw in design or manufacturing. If you are still under warranty please do not be lulled by these temporary fixes into letting your warranty expire (like I did). Also you will not get any answers out of Mercruiser. They will refer you to a dealer, who will simply try to delay you out of warranty. Demand a replacemnet now and you may get lucky and get a good carb. Currently I am exploring the possibility of replacing this Mercarb crap with an old marine Rochester two barrel. I am not sure if this will work. At best I will be spending a couple hundred more dollars and retrofitting a manual choke. I wish you luck."
