4.3l

D

ddzhere

Cadet
Joined
Apr 18, 2012
Messages
19
I have a 87 ebbtide with a 4.3L. The engine runs great from 1200 rpm up to WOT. Below 1200 rpm it doesnt idle well at all and below 1000 will die. At idle its puffing black smoke. Plugs,wires,cap were replaced last year. I'm assuming my mixture screws need to be adjusted?
 
wellcraft-classic210

wellcraft-classic210

Master Chief Petty Officer
Joined
Sep 22, 2010
Messages
839
Re: 4.3l

That does sound like a possible fuel mixture issue. The fuel is delivered through different carb passages at low RPM. The engine is also sensitive to anything that may be dumping added fuel at lower rpms. The black smoke sounds as if its possibly running rich. The idle screws dont narmally go out of adjustment.

Could be dirt in the carb, float seal and or float boyancy, fuel pump diaphram leakage in vent hose. Other ???

I would probably start with a carb cleaning and rebuild. Hard to say without actually seeing it,
 
Bondo

Bondo

Moderator
Staff member
Joined
Apr 17, 2002
Messages
70,513
Re: 4.3l

ddzhere said:
I have a 87 ebbtide with a 4.3L. The engine runs great from 1200 rpm up to WOT. Below 1200 rpm it doesnt idle well at all and below 1000 will die. At idle its puffing black smoke. Plugs,wires,cap were replaced last year. I'm assuming my mixture screws need to be adjusted?
Click to expand...

Ayuh,.... Welcome Aboard,... I'd sooner think the carb needs Rebuildin'....
 
J

joewithaboat

Lieutenant Junior Grade
Joined
Jul 3, 2011
Messages
1,172
Re: 4.3l

Would that not have a marine mechanical fuel pump, that dumps fuel in the carb if the diaphragm is leaking ?
 
achris

achris

More fish than mountain goat
Joined
May 19, 2004
Messages
27,468
Re: 4.3l

joewithaboat said:
Would that not have a marine mechanical fuel pump, that dumps fuel in the carb if the diaphragm is leaking ?
Click to expand...

Yep.... Good call. I've seen too many electric pumps lately and forgotten about the mechanicals... :facepalm:
 
D

ddzhere

Cadet
Joined
Apr 18, 2012
Messages
19
Re: 4.3l

Carb was rebuilt last year I guess it could be dirty again yet the filter is very clean. Could this also possible be a vacuum issue?
 
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