87 Mercruiser 5.7 3/4 power problem.

[inside0ut]

I have an 87 Wellcraft with a 5.7 mercruiser and have a power problem. When I throttle up it very smooth and there is no problem till I get about 3/4 power and then it seems to lag and stumble. It doesn't die when it does this... but it does seem like it pops and stutters. When I continue to advance the throttle, its perfectly fine and begins to increase in RPMs till it hits WOT. If I "drop the hammer" its accelerates normally and there is no issues. It seems to me as though its a problem when the secondaries initially open in the carb but I dont want to focus on that and lead anyone down that road. Anyone have any suggestions?

Thanks!

 

[achris]

Sounds like the carb needs cleaning out and resetting of all the adjustments. What carb is it? Rochester 4 bbl (aka Quadrajet)?

Chris.....