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Mercruiser 4.3 TKS wont idle

S

Sega

New member
Hi, my 2007 Mercruiser 4.3 TKS will not run on idle after starting up.
It has been stored all winter and started up just fine, but it wont run on idle.
I have changed oil, oilfilter, fuelfilter, filled a full tank of fuel, new spark plugs+++
It will run on higher rpms, but it it backfires when I pull the throttle back. With the boat in gear it seems to run fine at high rpms.
But starting it up again, back to the same old, no matter if its cold or warm, it doesnt run on idle.
I can hear the hissing of the TKS, so I am pretty sure that works fine.

I know a lot of you don't like the TKS but it ran just fine last summer, started up nice and ran nice.

The tip I have found so far that I will be trying today is to clean the carb with CRC carb cleaner, pretty sure that wont help, but I guess it's worth a shot.
The other thing I am doing today is cleaning the fuel inlet filter in the carb.

Any other ideas from you TKS experts would be greatly appreciated.
 
If it ran ok last year and not this year, adjusting it will not likely fix your problem. Likely ethanol related crap in idle circuit. ( been there, done that!). The gasket between the top of the carb and the body won't survive taking apart. It tears. After buying several of these (not cheap!) over a couple of seasons, I applied a thin coat of grease on both surfaces of my last new gasket before reassembly and was able to reuse the gasket ( at least once so far....hopefully won't have to take it apart again!!!)
 
EPA is blamed! But that didn't help much.

Could the problem be cold outside temperatures? It is around 40-45f over here in the land of the midnightsun these days.

I managed to get it running on idle today after "warming" up the engine on higher RPMs for a few minutes.
 
Not the "cold".... When I start my 5.7 w/TKS carb at those temps, it starts right up and idles at 1100 to 1200 RPMs until the engine water temp gets to about 130-140 degrees. All the while I can hear the trademark TKS "hiss", then it starts to fade and the idle eventually drops to 600. Hands off, don't have to touch a thing.
 
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