I was hoping someone could maybe give me some insight on this. I have an OG NeoTat 3.5 stroke and I can't seem to figure out what the issue that I am having is. I will explain the best I can. when running unloaded it is smooth and silent from 6v to 11.5v no problem at all, but when it is loaded It gets loud and chatters around 8v+ almost sounds like it is out of balance or there is a clearance issue somewhere.. I have tried to lube it a per the maintenance guide. I also ran it with no tube just a needle on it and found that it ran smooth until I put even the slightest pressure on the needle bar it would start to get loud.. Thanks For taking the time to read this and I hope someone may be able to give some insight