Sluggish when accelerating with some backfire

[Scrap1]

1996 3.0L/ LX mercruiser. Sluggish when accelerating from idle or a stop, eventually backfiring. However, once it gets to about 3000 rpm it takes off. Rebuilt the carb, no change.

 

[GA_Boater]

Welcome aboard.

Did you adjust the idle screw (s)? Is the accelerator pump squirting?

 

[Scrap1]

I believe you’re asking about the idle mixture screw, it’s 1 3/4 turn out. Not sure how to check that the accelerator pump is squirting?

 

[nola mike]

Look down the barrel of the carb and have someone push the throttle (engine off is fine). Should see 2 streams squirting...

 

[GA_Boater]

Or pop the cable off and move the linkage if you have no help.

Did you fine tune the mixture screws?

 

[Scrap1]

Yes, 2 streams shooting down into the intake.