Re: So what's wrong with the Merc TKS carbs?
Biggest problem (Customer complaints) I found with them, is they don't always work as designed. As John mentioned, they were designed to start in neutral at idle without moving the throttle, this is how the younger generation starts their cars and trucks with EFI. Problem is, most of the time you still have to pump the throttle to get the engine started even with the TKS.
Next problem is idle speed. It's supposed to be 700-900 rpm with a cold engine. In reality, they idle between 800 and 1200 rpm for 6-10 minutes before it's warm enough for the engine to go into normal mode.
On older models with chokes, you could just adjust the choke and use your throttle lever, and go as soon as the engine stays running, shifting and close maneuvering the boat at 1000 rpm is not only hard on the drive shifting, but too fast for the boat in close quarters.
With the TKS, there is no adjustment, if it idles too fast, then you replace the module. ~$200
Then you have the complicated system involved in making it work, plus it being a Mercruiser ONLY carb.
Basically what you have is a complicated, expensive system that doesn't always work, designed so people don't have to learn how to use their throttle lever. Might just as well have bought fuel injection, it's a lot more common and easier to work on and keep working.
