They make a few different fire detectors for marine use around the
motor. You could look into one of them as a possible starting point.

JFF

>This would be a very good investment.  Problem is with
>the heat from the engine, and the smoke from dirt on the
>exhaust it would be difficult not to get false alarms.
>I bet if one could come up with a good working system,
>this would sell as a nice aftermarket product.
>                                        ERic
>
>Anonymous Digest wrote:
>
>>Lots of good information has come and gone on this thread, almost to the
>>point of paranoia on some parts :-) It only makes sense to take care of
>>the fuel lines on any vehicle as old as our machines.
>>
>>As an observer, I conclude that the worst issue we face is the time it
>>takes for the driver to realize that there is a fire to be dealt with. Our
>>friend in NYC mentioned that others saw the smoke and maybe flames and
>>were frantically trying to get his attention. By the time someone outside
>>realizes the problem, and decides to take action to let us know there is a
>>fire, I its probably already too late to do much with a few fire
>>extinquishers. Those  who have reported their own experiences seem to be
>>split between those who did catch it early and got it out, and those who
>>got to it too late, with a horrific result.
>>
>>Just as in any other fire issue, prevention is top priority, but warning
>>is second. We don't usually install halon extinguishers in our homes, but
>>we always, I hope, have alarms and monitors that will alert us, to smoke
>>and flames, and then we grab the extinguisher, call for help, or do
>>whatever we can to control and put out the fire.
>>
>>The conclusion is that logically, we need smoke and fire detectors to give
>>us a head start on grabbing our extinguishers and fighting what would
>>hopefully then be a localized fire that we can control. Who will come up
>>with smoke and flame detectors that we can install in the engine bay, to
>>alert us the instant a fire begins to burn? I think that is the way to go
>>that makes the most sense.
>>
>>
>>
>>Just IMHO.
>>
>>John