4.3L Cough

J

jlash

Cadet
Joined
Mar 3, 2006
Messages
10
I just bought a 2001 Maxum 1800sr with a 4.3L Mercruiser alpha 1, carbureted v-6. When going from idle to full throttle I get a cough and than it will accelerate. The dealer told me when I test drove it to either lean or richen the mixture. I don't remember which one. Dah!<br />Can you please tell me which screw to turn and which way.
 
G

goldenjjg

Recruit
Joined
Jun 5, 2006
Messages
3
Re: 4.3L Cough

Is engine warmed up when this happens? You may want to verify if the choke is operating properly before you start turning screws.
 
J

jlash

Cadet
Joined
Mar 3, 2006
Messages
10
Re: 4.3L Cough

Yes, the engine is fully warmed up when this occurs. Only happens when going from idle to full throttle.
 
G

goldenjjg

Recruit
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Jun 5, 2006
Messages
3
Re: 4.3L Cough

Did you get any kind of warranty? If so, the dealer should take care of this. It could be an acc. pump problem in the carb. pull a couple of spark plugs out and see how they look. If everything is ok, they should be light brown.
 
bruceb58

bruceb58

Supreme Mariner
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Mar 5, 2006
Messages
30,478
Re: 4.3L Cough

Are you just jerking the throttle forward like when you are tryimg to get a skier up?<br /><br />Every carbed boat I have ever had has had this type of hesitation. It is a temporary lean condition. Check the function of your accel pump in your carb.<br /><br />I just make sure I push the throttle up more slowly.<br /><br />You won't be able to tell anything from the spark plugs abot the accel pump working or not.
 
bjcsc

bjcsc

Lieutenant Commander
Joined
Jun 1, 2006
Messages
1,805
Re: 4.3L Cough

To answer your question the idle mixture screws (provided you're running a Holley 4bbl) go in for lean and out for rich. Unlikely to be the problem, but worth checking the adjustment on. They should both be in/out the same amount. You can tell if you accel. pump is working with the motor off. You can hear it squirt when you hit the throttle. Another likely problem would be a blown powervalve in the carb.. If you bought this from a dealer you should have them fix it. A properly operating Holley shouild not do this.
 
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