1985 merc 9.8 very frustrating problem

[green4themoney]

Hey i recently rebuilt my merc 9.8 (new pistons, new rings, new seals, carb kit, fuel pump kit, Walbro WMB 3 carb, and the motor runs and everything.... i just cant get it to accelerate smoothly..... if i lean it down enough with the low speed adjustment it seems to help, but than its too lean to idle, and if i make it rich it will "chug" almost fourstroke from juat above idle untill about half throttle. Ive about had it ive tried everything with this motor.... compression is great.
.. everything else working fine.... just cant seem to fine tune it in

 

[racerone]

Is the "boost venturi " in place ?

 

[green4themoney]

Funny you should mention that, i ordered one for the carb cause the kit came with the wrong one... and it actually made the problem worse.... so i took it back out. I know its fuel related. Unless maybe its drawing air from somewhere? It seems with the venturi it runs even richer