!991 mercury 90 hp 3 cylinder,I rebuilt carbs fuel pump,fuel filter,put a new enrichening devise on.checked compression,and spark and there all fine.Motor starts great most of the time,Idles real good.But smells like its running rich.Even runs to full throttle with no miss.But if I throttle it up real quick and back down to idle it makes a burping -sneezing sound and stalls.some times.If I go from full throttle to Idle to Quick It makes that sound also and sometimes blows the little hose off that runs from top of the crank too the bottom of the crank,Then its a pain to get started.Also when throttling down quickly and it make that sound seems like smoke is coming from between the powerhead and exhaust leg.If I pull the little hose that is connected from the bottom of crank case,it smells like raw fuel.A friend of mine said that the gasket between the powerhead and exhaust leg will make it make that sound if its bad.seems to me there a lot of cranck pressure.but I'm no expert.But I like to no what you guys think before doing anything.Thanks in advance for any information