[mort]

Originally Posted by D.O.G.

Here's a paper that seems to be supporting fuel magnets.

Effect of Magnetic Field Strength on Hydrocarbon Fuel Viscosity and Engine Performance | Aktar | IJMCA
(Click on the PDF download near the bottom)

I'd be interested in any informed comments on their testing methods and conclusions.

There doesn't seem to be any discussion of their methods.
It looks like they ran one series of tests on each engine, diesel on a dyno, and a motorbike on a track. Seems like there are a vast number of uncontrolled and unmentioned variables that could be important. I'd like to see many more tests run in an arbitrary order. Maybe the diesel engine was stared cold, and as it came up to operating temperature it's efficiency improved? Each diesel test took between 77 seconds and 105 seconds. Which seems like a rather short run to get the reported precision.
This:
"The diesel consumption decreases till 4000 gauss and deteriorates beyond 4000 gauss... This could be due to other effects coming in picture post 4000 gauss field viz. viscous heating on the fuel on account of very high magentic filed strength." Is pure BS.

-mort