Outboards and Nat gas

[CDave]

Has any of the manufacturers ever experimented with Nat Gas in 2 Strokes?

[BarryStrawn]

Oiling might be a problem.

[Richard K.C. Mo.]

What about lp gas? With newer motors isn't the oil injected at the carb or injection system?
LIke to hear more on this as propane is consistently 30% cheaper than gas.

[Jay R.]

im pretty sure bombardier has worked at it, and i've read some articles about merc working on military outboards with alternative fuels....

[Mark75H]

Richard, propane costs more than gas here in the east. How much does it cost in KC? .... remember, to compare it to gas you must compare pounds to pounds, not gallons to gallons. Here in MD propane is 50 cents per pound and gas is still 33 cents per pound.

There is also the fuel tank weight penalty with propane; and with the greater distance between propane filling stations on the water .... you better have a big tank

[CDave]

Originally posted by BarryStrawn
Oiling might be a problem.

Injection oil should slove the problem.

[CDave]

Originally posted by Mark75H

There is also the fuel tank weight penalty with propane; and with the greater distance between propane filling stations on the water .... you better have a big tank

That is what I was thinking but with carbon fiber N20 tanks Propane tanks shouldn't weigh that much. Plus Propane will allow higher compression.

All in all gas make more BTU's IIRC. Just curious if any of the manufactures have played around with Propane.

[Blizz]

Mercs alt fuel motors run on jp5 jet fuel it's only for safety reasons on Navy vessels higher flashpoint.

[Richard K.C. Mo.]

Cost of propane at last filling about 3 weeks ago $1.25 per gal.
I fill my other tanks out of my 500 gal. tank even auto tank.

Permit cost is $75.oo a yr.
Eliminates a lot of road tax.

[BarryStrawn]

Originally posted by CDave
Injection oil should slove the problem.

Perhaps. One thing I remember about running 4 strokes on natural gas, LPG, and propane is the "dry" nature of the fuel. It doesn't wet the parts at all. I am certain someone could invent an injection system for the mains and rod bearings but I don't know how you would deliver oil to the cylinder walls. Maybe a mist system but would add a lot of new gismos. And if it worked, the engine is going to make less power and the boat will have to carry around more fuel and a heavy storage system.

LPG or Propane would probably work well on a four stroke outboard on a work barge or something where the weight doesn't matter and emissions are critical. More like what OLEGATOR was describing.

[CDave]

Originally posted by BarryStrawn
Perhaps. One thing I remember about running 4 strokes on natural gas, LPG, and propane is the "dry" nature of the fuel. It doesn't wet the parts at all. I am certain someone could invent an injection system for the mains and rod bearings but I don't know how you would deliver oil to the cylinder walls. Maybe a mist system but would add a lot of new gismos. And if it worked, the engine is going to make less power and the boat will have to carry around more fuel and a heavy storage system.

LPG or Propane would probably work well on a four stroke outboard on a work barge or something where the weight doesn't matter and emissions are critical. More like what OLEGATOR was describing.

Yes it is a dry gas but there is a company making a retrofit ele. oil injection.
Also with Nat Gas you have to bump the compression to get the Hp's close to gasoline. Nat Gas can handle high compression.

Anyway, I was just curious if it had been tried.

[Gerben]

Out here there's a company converting outbaords to LPG (liquid propane gas), not quite natural gas, but thought it might be interesting.

They used to convert 2str outboards too, but as its not cost efficient they quit on that. Nowadays they convert 4str outboards and mercruiser inboards. Claims are hardly any Hp loss, which sounds believable, as many cars over here run on LPG without Hp loss too.

A link to the company:
http://www.midlandwatersports.nl/home/lpg.html

Click on the LPG-inbouw button for some info..


Gerben

[Mark75H]

Cost of propane at last filling about 3 weeks ago $1.25 per gal.

The density of liquid propane and gasoline are enough different that you must use pounds and pounds to compare, not gallons and gallons.

at density of .51 I get 4 pounds per gallon, 31¢ per pound, 2¢ per pound cheaper than gas. Are you sure it is enough cheaper than gas to justify the effort and heavy tank?

[Richard K.C. Mo.]

Don't know about fuel density and things but i can tell you it costs me about $3.00 LESS TO DRIVE MY 84 FIOO FORD 302 powered pu 150 mi. Now if i drive that far every day i've saved enough to buy my beer.

Now if i could do that with my OB motor i'd be happy.
13 gal. lp=10 gal gas i believe about 80% +/- give or take/ more or less.

Doesn't gasoline weigh 7+# per gal? Way more than makes up for 38 gal lp tank.

Besides it sure burns clean , makes oil look really clean for a long time.


Don't want to get off subject too much, anyone remember blown flat named mr. clean?

[David]

There would be two ways of doing propane engine:

a) conventional 'carb'
propane converts to gas in carb outside of cylinder and is then mixed with air
propane vapor takes up more space than liquid gasoline
less air in engine = less power
no heat loss to vaporize gasoline in engine = hotter running= holes in pistons

b) direct injection

I don't know that DI solves all the problems with propane. You still have lower heat to vaporize the fuel = hotter engine. Not good for a two stroke.


My propane experience is with (a), in 4 stroke automobile engines. We got a lot of engine knock at high rpm and less power everywhere than gasoline.