....adding 20% bio-diesel to raise the cetane level resulted in virtually no loss of performance ...
I would not use bio-diesel.* This is the official position of Northern Lights/Lugger, regarding Bio Diesel as written by Bob Senter.
While biodiesel is certainly appealing in some ways, in its current
state of refinement it is totally unsuitable for long range cruisers,
sailboats, boats with very large tanks and standby generators. I will
post the chapter and verse technical background and recommendations
from John Deere, which are mostly in lockstep with other engine
Here's the short version:
1. Biodiesel degrades quickly, like milk. According to Deere, it must
be used within 90 days of manufacture, a near impossibility in marine
applications and standby generators.
2. Biodiesel's strong solvent-like properties do a great job of
cleaning normal accumulations of asphaltenes from tanks and fuel
lines; the freshly loosened debris plugs the filters.
3. Most of the flexible hose components, gaskets, seals, diaphragms
and O-rings will be gradually softened and/or dissolved by biodiesel.
The problem is insidious because the engine will run extremely well
until the problems begin.
4. Once the dissolved materials begin to enter the fuel system, fuel
injection system failures and upper cylinder failures can occur -
these materials were never designed to be burned in the combustion
chamber. External leaks and filter plugging are the least of your
worries. The longer term fuel system and engine component failures are
likely to be much more oppressive and expensive.
Without debating the merits or challenges of biodiesel, I hope that
these challenges are overcome in the not too distant future. The
reality for now is that it really only works well in some highway
vehicles and agriculture/ construction equipment where all the fuel is
consumed in a few days.
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