Running Spoilt Gas/Petrol in a Yamaha 2 Stroke 150 AutoLube Outboard?

Hi Guys!


Need a little help, I recently brought a small 18ft/5.5m speedboat with a Yamaha 2 Stroke 150hp Auto Lube Outboard, I use this mostly in England UK, it has a 40L/8.8Gallon petrol tank, and I get about 15-18 miles out of it on water. Petrol prices are not cheep over here, so I was wondering if I can run "spoilt" petrol/gas in it? Spoilt being gas/petrol mixed with diesel? as I might be able to get hold of spoilt gas very cheaply, hence the upkeep would be much more affordable.


The engine in question:
https://www.dropbox.com/s/0j89ylo2yz..._2008.jpg?dl=0
https://www.dropbox.com/s/v4uecz6z09..._2009.jpg?dl=0


Thanks for any help you guys can give me!

No you cannot run any kind of diesel in that motor. You will have to stick with straight gas. I would be surprised if it even ran halfway decent with that mix.

If you want to save fuel never run it WOT. With the engine off in forward gear advance the throttle to max timing advance and put a mark on the controls. You should get your best economy at that point and keep it at 87 octane rating.

Unfortunately UK has 95 as the lowest octane you can buy, even with the barrel prices at the lowest with in 12 years, a price of 1 litter of 95 is £1 which is $1.47 = $6.61 a Gallon

This means it's costing me $58 a full tank to go 15 - 18 miles on it, I've got to find a way in running this more cheaply or unfortunately I'm going to have to sell it

How long have you owned the boat? All you can do is slow down, try different trim angles and shift weight in the boat. You should find the sweet spot with your setup. Is the motor running close to 100%, the hull clean and the prop in good shape? Just take your time and enjoy your time on the water a good little kicker might help depending what you use it for.

You know that since no one in the US has ever heard of "...Spoilt Gas/Petrol...", perhaps you should research it a little further with those who know...

It could be just from a run switching a pipeline system over from pumping diesel to pumping 95 octane. A small amount of diesel wouldn't harm your engine.

You sure wouldn't run it in your Bentley but might work in your boat. You also couldn't run the typical petrol/oil outboard mix in your Bentley either.

Around here, there are so many "Low Speed" zones (and that's worst case fuel efficiency in a Yamaha 2-cycle) I added a 4-stroke/10 HP Honda to do that work and my overall fuel burn is well below 3 gallons per hour over the past few hundred hours.

At higher speed, the 2-Stroke Yamaha 90 is equal in fuel efficiency with a 4-Stroke.

See if you can find an Octane rating for this mix since it may just give your engine a little extra lubrication without any detonation damage. And if it were just a little low (like 84 or so), your high throttle lever spark advance could be moved from 22 degrees (or whatever) to a lower BTDC to prevent any detonation, or you could mix with a little 95 to bring it up to 87.

During The War, your Grandparents were running their petrol cars on Kerosene (usually called paraffin in the UK, with a timing adjustment) and today, the RAF powers their fastest Jets on Kerosene. (Jet Fuel is just refined kerosene with a little petrol added in some military applications.)
Art

A tow-in is going to cost you a lot more than $58!

Correctly propped and installed, that engine burns 30lph at 4000 rpm. You are either running it too hard, have an installation problem, have a problem with the hull, aren't trimming correctly, or have an engine problem (maybe the LP fuel pump diaphrams).