LPG conversion on a boat!

Post by **AndrewSkinner** » Thu Jan 24, 2008 12:04 pm

Ok this one has been bugging me for ages!!

Aswell as my morris project I am also restoring a speed boat!

The power for this boat comes from a 40hp Evinrude petrol 2cylinder engine. (but runs on a petrol & oil mixture/2 stroke)

Is it possible to convert a 2 stroke to LPG AND is is possible to convert a outboard boat engine to it??

Post by **Orkney** » Thu Jan 24, 2008 12:47 pm

Think no - because with a 2T the cylinder lubrication comes from the oil content of the petrol. (at least thats my understanding of it)
My last 30ft offshore worker had a 175 performance outboard engine which was 2 stroke but had a seperate tank for the oil - 70 gallons fuel per hour flat out, it had to go

Post by **bmcecosse** » Thu Jan 24, 2008 1:21 pm

As Orkney says - you would need to find a way of drip feeding oil in with the air - not impossible, but maybe challenging! And even then - without the liquid petrol to carry the oil round the working bits - I think it would be likely to seize up PDQ. Best to try to get a 4 stroke outboard - then it would be easy enough. But will you use the boat sufficiently to save anything near the conversion cost ? Better perhaps to put the Minor on LPG - in a year it's surely likely to be the greater user of fuel.

Post by **AndrewSkinner** » Thu Jan 24, 2008 1:29 pm

haha Orkney!! nice one! these things are so bl**dy expesnive to run!! at the moment it is also runing rich!!!!!! put £15 of petrol in and running flat out its gone in under 1/2 hour!!!!

We are toying with the idea of putting in a small diesel generator and using an electric outboard.

Allot of the comercial outboards are, well....pathetic to say the least and you will have to re-morgage your house to buy one! lol so we have sourced an electric motor from a small electric car going cheap!!!! with 11hp const. and peaking up at 35hp at 72v it should be a very nice set up!!

and i have found a website that claim they can convert 2stroke engines with a mixer!! they are made for tuc tucs!!!!!!

Post by **Orkney** » Thu Jan 24, 2008 1:41 pm

The only trouble is with what your suggesting .... your then relying on 2 motors not one for primary propulsion, a BAD IDEA when at sea even say coastal to 15 miles.
Your doubling the risk of your having a problem.

Post by **AndrewSkinner** » Thu Jan 24, 2008 1:51 pm

we only use the boat on the river and there would be a small battery bank.

We have encountered engine probelms before and therefore carry paddles all the time anyway.

Dad runs a yachting club so hes always keeping a good eye on the project! sometimes when we dont want him to!!

Post by **10852sm** » Thu Jan 24, 2008 10:36 pm

Speedboats are nearly as much fun as Minors!

It sounds like your outboard is running very rich, I had a 14ft speed boat with 40hp Yamaha 2 cylinder engine, the Mariner/Yamaha one from about 1985, we would waterski for about 5 hours on a 5 gallon tank of 100:1! Fantastic engine!

Have fun

Steve