3.0TKS under load the engine boggs / almost stalls

[Notaboat Mechanic]

I have a new 2010 Mercruser 3.0TKS 1A325389 Alpha 1 drive 1A250099 with only 5hrs. I took it for a spin at the dealer and there was no issues, the service tech did mention a slightly rough idle and that he would adjust it, I didn?t take notice. I winterized it and there she sat all winter from Nov2010 till May2011. Last week I de-winterized it and took notice that the idle was rough, so I let her warm up then made a minor adjustment on the idle screw till she smoothed out, which was a high 1000 rpm (normal should be around 800). I put her in the next day and that?s where the problem began, in gear under load at low RPM (1000-1200, no wake style) there does not seem to be an issue, however when I advance the throttle (not a hole shot, just a normal advance) under load from 1200-1500/2000rpm the engine boggs or almost stalls, I ease back then advance again and she planes right up. At that point I can jockey the throttle around at various higher RPMS and everything ?seems? ok accept there does seem to be a slight lack in throttle response or hesitation. But I?m not sure if that was me expecting more or an actual issue. This happened the entire ride which was 2hrs, so now the motor is at 7hrs. The next problem was when I brought her back to the dock and put it in neutral she almost stalled. After I got the boat home I flushed the engine (not under load) and took notice that the RPM was running rough at 1000, so I made another adjustment bringer here back to 800 where she smoothed out and advanced the throttle a bit there was no stalling/bogging.
I have been reading a lot of information in books and on the net and everyone has their opinion. I am a jet engine mechanic by trade; I troubleshoot and run jet aircraft engines, so it?s hard for me to just turn my problems to a mechanic hoping for a fix. Call it pride in ownership; I should realize I am a jet engine mechanic not a boat engine mechanic.
So before I break down and use the 2yr engine manufactures warranty, this is my course of action. I plan to take this one step at a time. First, I will install a fuel water separator because the 3.0 do not come standard with one, and then take her for another spin; if that still does not correct the issue by that time I should have used up most of the fuel and will fill up with ?fresh? fuel. If there is still a problem the manual says the tech can correct most bogging issues with an adjustment lever on the carburetor, so I will do that trying the other 2 setting options one for more fuel and one for 1.0 less fuel. If by this point nothing works then I will cash in on the warranty and take it to the service technician who will most likely ask me if I put fresh fuel in it.
Is there anything else anyone would recommend?

 

[Pete104]

Re: 3.0TKS under load the engine boggs / almost stalls

Chances are the "warranty" isn't going touch a fuel problem. If you start playing with it. Don't touch anything, take it back to the "dealer" (I assume)& tell them, that it has been unacceptable from day one! Call Mercury, also. The TKS system is not something they want customers playing with. You are not out of line by getting them to fix it to your satisfaction.
Pride has nothing to do with it! You earned it!