Startron Diesel Additive- http://www.westmarine.com/webapp/wcs/stores/servlet/producte/10001/-1/10001/141656/377%20710/0/diesel/Primary%20Search/mode%20matchallpartial/0/0?N=377%20710&Ne=0&Ntt=diesel&Ntk=Primary%20Search&Ntx=mode%20matchallpartial&Nao=0&Ns=0&keyword=diesel&isLTokenURL=true&storeNum=6&subdeptNum=169&classNum=764

I had a bad case of what I thought was algae in my 85SD. The engine would crank but not start & tank was nearly full. First I changed filters. Glow plug system tested good. Still no start. I dumped Startron in & let it sit until the weekend when I had more time to work on it. Cranked it & rattle, rattle rattle just like normal. At least try to start it before you go to the trouble of draining. Diagnose if you have a problem. These cars have a reputation as bullet proof for a reason.