Gas powered outboards

[Graham_Wright]

On a stand adjacent to ours with a very enthusiastic American gentleman selling.

He had very convincing arguments and the price was not much more than petrol.

Any views?

 

[FishyInverness]

It's been discussed here before - were generally outed as not a good idea IIRC - I'll see if I can find the thread....

 

[jakeroyd]

Sort of covered here.
http://www.boatingmag.com/boats/lehr-propane-outboards

I was in ProMarine in Plymouth the other day and they indicated they were agents for Lehr.
Competitive prices too.

http://www.ybw.com/forums/showthread.php?408907-Next-phase-of-Outboard-emissions-legislation

 

[Fantasie 19]

Wasn't there a review in this months (or last months) PBO mentioning them??? From memory I seem to remember that the salient points were that they were expensive, start first time however cold, and gas storage is an issue....

 

[srm]

Having seen one demonstrated at the Toronto boat show the exhaust had a funy smell. I think it was Lehr, but the sales rep would not say who built the outboard, just "an imported motor with the carb replaced". Might be an idea to try and discover who makes the base unit for getting spares if going down that route.

 

[pvb]

Why? What's the point? Surely petrol is much more convenient?

Having said that, I recently bought a Torqeedo.

 

[simonfraser]

if you could run it off your gas for cooking & ? heating supply, perhaps, else, whats the point ?

 

[DownWest]

I had a gas powered generater. Give me petrol any time. Motor is probably Tohatsu, since many small outboards use the engines.

 

[DownWest]

On a stand adjacent to ours with a very enthusiastic American gentleman selling.

He had very convincing arguments and the price was not much more than petrol.

Any views?

And, I would be interested in the `convincing arguments'

 

[Jabs]

Why? What's the point? Surely petrol is much more convenient?

Having said that, I recently bought a Torqeedo.

Why would I want petrol on a boat with diesel and lpg?

Tony

 

[Jabs]

Having seen one demonstrated at the Toronto boat show the exhaust had a funy smell. I think it was Lehr, but the sales rep would not say who built the outboard, just "an imported motor with the carb replaced". Might be an idea to try and discover who makes the base unit for getting spares if going down that route.

I understand it's Yamaha.

Part of my decision to buy one!

Tony

 

[Jabs]

Wasn't there a review in this months (or last months) PBO mentioning them??? From memory I seem to remember that the salient points were that they were expensive, start first time however cold, and gas storage is an issue....

Don't understand why gas storage is an issue.

Our gas locker contains:

Calor gas bottle
Camping Gaz bottle
Disposable bottles for BBQ
Coleman bottles for outboard

Can run the outboard From all but disposables from BBQ

How convenient is that?

And no risk of petrol in the bilge!

Tony

 

[JumbleDuck]

Having seen one demonstrated at the Toronto boat show the exhaust had a funy smell.

Autogas (propane/butane) is naturally odourless, so they add some smelly stuff to alert you to leaks. The smelly stuff they use, methyl mercaptan, doesn't burn in the engine, though, so the exhaust smells like a gas leak, which can be worrying until you get used to it. Perhaps the stuff the outboard people were using was similarly treated.

I have a Citroën DS which runs on LPG. It's great - quite apart from the cost it burns beautifully cleanly, so when I change the oil at 10,000 miles it comes out almost the same nice yellow colour as when it went in. LPG needs a juicier spark than petrol, so the ignition system has to be in perfect nick, but that's the only downside I've found.

However, I really can't see the point of an outboard like the Lehr running these titchy cartridges. I know they can use their own external tank, but it would be much better if they could use the boat's gas supply. Maybe a standard gas bottle can't evaporate the stuff fast enough though. You need about 15% of the combustion energy to vaporise propane - in the car that comes from the engine cooling system but a boat's gas bottle would have to take it from the air, and 15% of 3kW is a fair bit of cooling.

 

[Fantasie 19]

Don't understand why gas storage is an issue.

Our gas locker contains:

Calor gas bottle
Camping Gaz bottle
Disposable bottles for BBQ
Coleman bottles for outboard

Can run the outboard From all but disposables from BBQ

How convenient is that?

And no risk of petrol in the bilge!

Tony

I don't have a gas locker... in the kind of boat sizes that would use an outboard as main automotive power, I suspect I'm not unusual in not having one...?? So not quite so convenient..

I understand they won't go far on the disposables??

 

[VicMallows]

Biggest problem is that they are still 4-strokes and therefore just as fussy about which way up they are kept as a petrol. (I simply have no idea how I could maneuver any 4-stroke on/off my tender single-handed ...... I guess if my 2-stroke ever dies I will have to go electric).

 

[Lakesailor]

LPG tends to have less peak power but deliver more torque at very low revs than petrol.
Lots of trials cars use it for this very reason. Not sure they are so important for outboards. Cold start isn't as good. Many petrol/LPG conversions are started on petrol before switching to gas once warm. If the carb is removed and fitted with a gas carb you don't have that choice.

 

[Lakesailor]

LPG tends to have less peak power but deliver more torque at very low revs than petrol.
Lots of trials cars use it for this very reason. Not sure torque is so important for outboards. Cold start isn't as good. Many petrol/LPG conversions are started on petrol before switching to gas once warm. If the carb is removed and fitted with a gas carb you don't have that choice.

 

[JumbleDuck]

LPG tends to have less peak power but deliver more torque at very low revs than petrol.
Lots of trials cars use it for this very reason.

I think it depends how you set it up. The DS is adjusted for the gas mixture to be as right as possible between about 50 and 70, and though in practice I don't notice any difference at lower speeds it definitely runs rather better on petrol at 100. I believe I could have it set up to run well on gas at high speeds, but then I'd lose lower end flexibility.

That's all open loop stuff. A modern closed loop system with lamda sensor ought to be indistinguishable from petrol.

I have to start on petrol, by the way, and if I change to gas before the thermostat opens the vaporiser freezes.