I've got a 1990 16 w/ a 4.3 OMC. The previous owner had someone try to get more speed by changing the jets in the secondaries. I'm not sure what else was done. The engine flutters when going from 3/4 to 7/8 throttle, and smoothes out when wot. It eats fuel like there's no tomorrow. I've contacted some Carb. rebuilders, but something tells me no matter how much I tell them about the secondary jets, I'll still get a run of the mill rebuild kit installed and still have this problem because the jets won't get changed to a stock size for my altitude. For all I know, the spring in the diaghram has been changed. What I really want is a replacement carburetor and so far no one has one on the shelf. Jeggs has a brand new one on the shelf for $411.00, and at this point in the season, I'm tempted to get one. Any advice? Thanks, Russ