Originally Posted by itsaboat
I have an MD5B. I would have to guess it is air. I could not get mine to start for anything after I bought it, and finally resorted to a little squirt of starter fluid in the air intake. I was told never to do this by the fine folks on this forum and others, but after using the same method for years growing up with a John Deer farm tractor, I thought I would give it a try. Been running ever since. Your mileage may vary.
It is my understanding that it is OK for direct injection engines but very bad for pre-combustion chamber engines. I had a 3-71 Detroit diesel and used it all the time, just a brief whiff. Out of desperation on a minus 15 degree, Fahrenheit, day and a dying battery I used just a slight bit near the intake of a VW diesel and got away with it. However, I have seen pictures of the head of a pre-chamber engine that suffered big time, new head, damage from using ether. I have read WD-40 works and may not be as volatile.