I just did a decarb on my 1968 6hp and now it doesn't have power in forward gear, seems fine in neutral. It doesn't have the rpm and it will quit at WOT. But every once in a while i will restart it and it has normal power, but eventually quits again at WOT. Could the decarb have caused the problem? I used sea foam through the carb. Should I rebuild the carbs now?