I would bet the carbs were plugged regardless. You have multiple issues I'd guess. Hold your bulb straight vertical and pump it to see if it gets hard. If it doesn't you have either a fuel pump issue. Or if fuel runs out the overflow in your carbs you have a float bowl issue. Only achieving 3000 rpm's means one of several things. Low/lack of fuel to the cylinders. This can be caused by multiple things. Or your rings are stuck on your pistons. linkage not opening carbs as far as they need to be. One other question. When you start it at home on the muffs did you put it in gear and make sure the prop turns freely?
Can I check this by taking the air box off and just looking in the carbs while I pump the primer?