What happened to marine outboard engines?

[Rodney]

New to this list and have a general question.

Seems like there has been a lot of work done on auto-engine conversions, redesigned vw engines, corvairs etc, even a Mercedes aluminum block diesel engine conversion.

Why don't I see or read about anyone converting the many types of 2 cycle/4 cycle outboard engines for use in an experimental aircraft? Is it a weight problem, redrive problem - what???

Thanks
Rodney

[gunther]

Rodney, I talked to a fellow once that tried converting an outboard for aircraft use. He discovered that the outboard cooling system was designed for open-loop cold water cooling and there was insufficient flow and heat transfer when operating with a closed loop at higher water temps. This makes perfect sense because heat transfer from one medium to another varies as the temperature difference between the two mediums. In other words, the outboard was designed for cooling with cold lake water.

Gunther