Propane Outboards

[Poly]

Originally Posted by Wild_Bill

I think these engines are cool. I hope they become popular. I especially like the reduced emissions and that LPG can't be spilled in the water like gasoline. However, I would not buy one. I would worry about being able to tell how much fuel is left and also fuel availability. The killer for me, though, is that the Honda 20hp can be purchased for US$3,000 and weighs 104 pounds. The LEHR 15hp can be purchased for US$2,930 and weighs 110 pounds. That's apples to apples: both are short-shaft, tiller, rope-start.

fuel should be available at most camp sites, marinas, and certainly in the UK many petrol (gas) stations and dit/garden stores... So probably more widely than waterside petrol and without the odour issues of transporting liquid ffuels in the car. In terms of knowing how much is left weight is easy to estimate and to measure reasonable accurately. This is how I tell how much petrol I have left as portable tank gauges are so unreliable.

[simsy]

LPG can be filled up (people I know fill normal gas bottles with an adaptor with LPG at the petrol garage for their caravans)... so no need to use the left over gas on another thing)..

Octane is more about rate of flame not calorific value...
I have always liked the idea of LPG outboards, so an interesting read for me...

[Nos4r2]

I got to see a couple of Lehr propane outboard in the flesh last week. No comments on how it runs, but I did take some pics.

It was in Florida, so cold running probably isn't an issue. Prices are obviously in $.

Please excuse the crap pics, I was trying to take them without attracting a 'helpful' salesperson which meant the camera stayed in it's waterproof housing and was out for the shortest time possible.

[Rokraider]

I have a couple of Jeeps that run on LPG. The drop in performance is quite noticable. My Grand Cherokee (4.7 275 BHP V8) has a 90 litre tank. from empty it will only take around 75 litres to fill it up. I can usually get around 225 miles to a tankfull. It wont start on LPG from cold,usually it has to run for 5 minutes before it switches from Petrol to LPG. Average price seems to be around 70p per litre. The engine is less efficient on LPG and burns more of it to do the same job as petrol. When it is getiing down towards 1/4 of a tank of LPG, you have to avoid any erratic driving, as it will make the engine hiccough if the LPG is sloshing about in the tank. It is only the fact that the pump price is a lot cheaper that justifies its use.
On an outboard, I think there will be several issues. First starting from cold. It is going to burn more LPG than petrol doing the same job, so the performance and range is going to be down. The pressurised container is probably heavier than a petrol tank.
If it is getting low on LPG in choppy water where the boat is getting pitched about, it may well cause the engine to hiccough and cut out. Overall, I wouldn't have thought it was worth the inconvenience and additional cost for the conversion of LPG on an outboard. If it had a large LPG tank under decks with a decent capacity and a seperate fuel tank for starting and rough conditions when the LPG is getting low, then it might be worth a go?
Also LPG doesn't lubricate the valves and seats and will destroy the normal seat (including unleaded valves). You can fit hardened Valves and seats, which will sort out the problem, but it is more cost of course.

[Crusher]

These are available in the UK
http://www.lehruk.com

I Have nothing to do with them, but in conversation I was told....
1. They run on the small disposable camping cylinders.
2. One of these cylinders will have a very simular range to a 5 litre fuel can.
3. These are not "converted" outboard petrol engines but are propane engines. (I'm sure the have cold starting and engines designed for this... It's not rocket science)

All only my opinion.... But is would be great to hear from someone who has actual experience of one..... 👍


Sent from my iPhone using RIB Net

[Nos4r2]

Originally Posted by Crusher

These are available in the UK
Lehr UK | Propane powered outboard marine engines

I Have nothing to do with them, but in conversation I was told....
1. They run on the small disposable camping cylinders.
2. One of these cylinders will have a very simular range to a 5 litre fuel can.
3. These are not "converted" outboard petrol engines but are propane engines. (I'm sure the have cold starting and engines designed for this... It's not rocket science)

All only my opinion.... But is would be great to hear from someone who has actual experience of one..... 👍


Sent from my iPhone using RIB Net

The 5hp pictured uses a screw fitted cylinder, about 1.5 litres in size.Same diameter as our disposable cylinders but about 3 times the length. Quite large for a 5hp motor as well.

[m chappelow]

Gas may also freeze up cold conditions .

[tonto]

Originally Posted by m chappelow

Gas may also freeze up cold conditions .

That depends upon what gas it is.

At atmospheric pressure Butane has a boiling temp of between -4 and -10 C depending on what type of butane it is, whereas propane has a boiling point of around -41.3C.

So if you have Butane, and the temp is below -4, you are likely not to get any gas vapour out of the bottle, as you are not going to get any pressure in the bottle to push it out.

If you get propane, then that is not an issue, but propane bottles have to be heavier and withstand more pressure, as at ambient temp( +15 C ) then butane remains a liquid at about 4 bar, whereas propane does the same at 15bar pressure.

LPG as sold in blue bottles AFAIK is butane and propane red bottles, although there is some LPG sold as a mixture of the 2 which is dependent on seasons.

[Maclures]

I too am interested in the propane outboard , and got in touch with my nearest dealer 120 odd mile from me :-(, but I got told that a 5kg propane would run it for 6 hrs this is the 9.9hp and he did say you do get 9.9hp so no loss of power ?

There are refillable propane light weight tanks to fill at garages, only thing putting me off is the 9.9 weighs 39.8kg, As I have just had a triple hernia and two tumors removed, so now not really sure what ill be lifting for long time.
£2250 cant remember how much warranty you get.

[Tom]

You don't have to run the LEHR on small screw in gas canisters you can buy quite large refillable gas bottles and connect them up with a hose.

One big advantage for me is the garage of my motorhome can be accessed via the fixed double bed so when the engine is put in the garage there is no chance of my motorhome stinking of petrol.

[Dankoozy]

Originally Posted by Turbodiesel

I spent a year or so trying to modify outboards to run on LPG with little success! We had some LPG experts helping out from a few companies but we could never get them to run well and yes they loose power when running on gas! The biggest problem we found we could never get the gas hot enough to burn properly, which cause the engine to stall when you shut the throttle down, also the massive assize head ache of trying to pass all the regulations for keeping LPG on a rib it was just not worth the hassle. We did sell about 10 15hp Mariners that were converted with t prins LPG system so they must be about somewhere, and we also converted a few Merc 60 four strokes. They never really ran very well when on has and we just used to run the on petrol most of the time!

How were you heating the gas? I have a converted LPG hilux with a heat exchanger connected to the cooling system to warm up the gas but the water flowing through an outboard would be much cooler.

Maybe one would have more luck converting an outboard with closed loop cooling if those ever catch on

[Maximus]

Originally Posted by shinyshoe

b&q...