4.3 Merc Cold start flooding

[johnnyb-21]

Hello all,
Lately I've been having cold start issues with my 03' Stingray 190LS. 4.3L Merc. At cold start, it takes a few tries to get it runnung and once started, it floods and black smokes really bad for a minute or so, then works fine. It works perfect when warm, no issues at all. Even if engine has been off for only 20 minutes, when started, a puff of black smoke is visable for a second. I have tried adjusting choke, it's almost full lean now, but no help. Any advise for a newbie ??

 

[Alpheus]

Re: 4.3 Merc Cold start flooding

I don't know what kind of carb you have, but it sounds like your carb has an internal leak. If you have a Quadrajet it usually is leaking well plugs. If you have anything else this could be a leaking needle/seat or heavy floats...

 

[cr2k]

Re: 4.3 Merc Cold start flooding

On a Rochester or MerCarb there are tiny holes in the top of the venturi block -the pieces that screw down from the top and extend into the opening - if these got plugged the carb will siphon gas into the carb throat when not running.
right after you shut it off pull the flame arrestor and see if there is any fuel fogging or dripping in the openings.