Re: Propane outboard?

[boxcar]

I have been running propane and converting vehicles to propane for many years.
I build off road ( 4×4 ) rigs. Propane makes sense on these rigs as a propane powered Jeep will run nearly upside down.
I have never found that it adds hp or economy. It does the exact opposite . Lower economy and a marked reduction in HP.
All of this means nothing in an off road rig where gearing overcomes all deficiency’s.
As stated earlier, your octane ratings are a mystery. I would guess the alternative fuel data center .
A green bio fuel advocate. Who’s data should be scrutinized. They use words like " comparable , and similar " often, rather than just stating that the fuel is just not as efficient .
They also advocate propane’s use in cold weather climates stating that it cold starts better than gasoline engines .
This is true . What they don’t and won’t talk about is its tendency to freeze up and turn the carburetor into a large chunk of ice in cold weather.
Or it’s rather dramatic loss of efficiency above 3000 ft altitude.
Octane ratings for propane run the gambit from claimed 75 up to 115 octane.
I tend to believe the lower numbers. Call me a pessimist….
I never stated that you were trying to sell kits . Rather that you got your Octane information from someone who was trying to sell kits.
The hard fact is that in a boat , propane is a known hazard. It always has been and always will be.

LPG (Liquefied Petroleum Gas) is kept under pressure as a liquid
and when released, becomes a highly flammable gas that is much
heavier than air. The gas industry also knows it as one of the most
searching of gases, that is, it can escape through gaps that would
hold water and other gases.

On boats, the Liquefied Petroleum Gases in common use are,
‘commercial butane’, and ‘commercial propane’. They exist as gases
at normal temperatures, but become a liquid under moderate
pressure. Propane turns into gas at a lower temperature than
butane, so the storage pressure for liquid propane is slightly higher
than butane.
One volume of liquid butane or propane produces approximately 250
volumes of gas and thus a leak of liquid is a grave hazard, especially on
a boat. Since LPG vapor is denser than air, leaked LPG vapor will fall
and flow along cockpit floors, bilges, etc and the vapor may travel
some distance. The LPG will build up in low-lying parts of your boat and
it may persist for some time.
It only needs concentrations of 2–10% LPG in air to make a flammable
mix. In a boat, a flammable mix will explode if ignited. It is also possible
for gas/air mixtures from leaks or other causes to be ignited some
distance from the point of leakage and the flames travel back to the
source before exploding. In extreme cases, if the cylinder is lying on its
side; if the cylinder valve is faulty; or if the exposure to the fire is
extended, the cylinder may rupture leading to a violent explosion.
Alternatively, the point could be reached where the pressure-relief valve
releases LPG, causing a significant jet of burning gas.
To help prevent incidents, a stenching agent is added to give LPG a
strong odour, which most people can smell long before the gas reaches
dangerous concentrations.
[Based on information from the LP Gas Association]