I fixed Mine!!!
.....Well I fixed it twice actually. Mine was sagging within a sixteenth of rubbing on the bottom. The fix you ask. Well I had bought a new air compressor and had some vibration dampners that I bought for when I install my compressor in the new shop. (Look up FS Curtis dampners) I pulled my machine yesterday and set it on some jack stands and took all the bolts from the four corners of the machine that hold it to the frame off. I then took two mini jacks and jacked up the motor and generator from the frame and pulled the old dampners. the FS Curtis dampners fit perfect in the back on the motor and have a wider foot print than the stock ones. The stock ones on front I took out and cut down the new dampners to size and had to shave them down abit to where with alittle soapy water and a mallet they squeaked in. I let the machine rest back on the frame and rubber mounts and it sit back to perfect in the frame. The not so old stock ones that I took out looked like they came out of a twenty year old machine. I have never had this problem on other previously owned machines including my 2011 SAE 300. The only thing that I can come up with is maybe Lincoln switched vendors or the rubber on the newer machines are not as dense as on earlier models. Well after day one and a few miles down oil field roads my nose cone was back to sagging but not as bad as it was so I pulled off the machine again this evening it looks like the back ones on the motor are going to hold up well but the front was to much for the rubber up front so I pulled them off and put the old ones back in and added a piece of 3/16" mud flap that I had laying around on top of the old ones. Now the machine sits slightly above center and I am thinking it will find it's final resting place somewhere close to center.
All that said I did talk to Lincoln directly today and they were talking about A derometer of 65 up front and 40 in the back and blah blah blah. Whatever the case they are gonna send me some new ones which probably won't be seeing my machine. I did call my LWS where I bought my machine and told him to find out if the rubber on three hundreds are different than the two hundreds and if so order me some back up ones for a 200D.
I will post some pics of the new rubber fix tomorrow. I have seen many of the new 300's doing this and have a feeling that there is some sort of connection to this and the main bearing going out as I have had a few guys I have worked with have had that problem. All of them 2012 and newer.
Anyways hope that points some one in the right direction