OT but think this group will know answer
 

Looking for a 'super garden tractor', came across a mid-80's Cub Cadet Model 1914 (at least 914 is part of it), 19hp Onan, rear PTO, 3pt hitch, 60" deck, 45" 2-stage blower and a 42" tiller. Anyhow, the thing caught fire about a month ago and has been traded into a dealer who wants $1,800 for it. The question for the group is this: hardly any fire damage because the owner was near the house and was quick with a dry-type extinguisher. However, now the engine bay is full of a couple of pounds of drychem. What is the best way to flush that stuff out of there, hopefully without ruining something else?

AFAIK, Nothing.

The popular dry-chem agents, at least the ones in use a few years ago, eat aluminum and also wiring insulation. Often quickly. Jake has a couple of stories about the helicopter engines he used to work on...

The damage is likely already done. I'd walk away.

--DD

Not all dry chem is the same. Jake was probably dealing with PKP, which is nasty, but some of the dry chem type agents are more innert. If there is any exfoliation of the metal then you will know what type you are dealing with. It should be obvious if the tractor is terminal.
HTH