Greg,
diesel pumps RUN on diesel fuel, but they are designed AROUND it! You say 90 minutes your running on etherless, could detail the mix?, it seems a bit short time, maybe 30 hours will be an acceptable goal. I hope you will attain it.
For D-STAR, those engines cost in the order of thousand dollars, if and when in production, and claim to be designed for working with lubrication of around 1 centistokes, the same as for diesel pums. But no model engine manifacturer claims this value. I think that if something happens they will declare their warranties void!
For an example of what is happening (wearing) around simply by substituting diesel with Jp8 take a look at http://www.findarticles.com/p/articl...n15648548/pg_1