Correct Fuel Mix

[muzzburt]

Hi Guys,

I have 90s 60hp 2 stroke yamaha, got a few questions about fuel

Can i run it off E10, or Unleaded only?
what octane rating?
Fuel to oil ratio?
What oil to mix is best?

Thanks in advanced!

Muzz

[Crocodile]

Hello Muzz,
Under no circumstances use E10.
Unleaded is fine.
50:1 oil ratio.
Use Yamalube.
I assume that this motor is not self-mixing, does it have an oil tank under the cowl?

[muzzburt]

Thanks for the reply!
Yes there is oil tank.

[billfisher]

If it has an oil tank then the motor sets the fuel to oil ratio, ie you don't add oil to the fuel. Don't use E10. Where I live it's hard to fine ULP 91 without ethanol so I have to buy ULP 95, ie premium. My 2 stoke seems to run a bit better (more power) with the premium even though it doesn't have an octane rating sensor (something about the way premium fuel combines with oxygen).

[Fed]

Muzz, if the motor is new to you run some premix in the tank until you confirm the oil usage and test any alarms if it has them.

[boboncc]

Interesting ......... I have not had anything to do with outboards but I'm looking at getting a 25HP Yamaha, I was told by the dealer's service bloke that you do the first 10hrs at 25 to 1, after that at 100 to 1. The first seemed to be very rich and the second lean (oil wise). He did emphasise you had to use Yamaha oil, I thought that this may have been to get you to use their product.

I guess the older motors may have run on 50 to 1 but if it is an auto mix system, I don't think you should have to worry about it.

I've seen several warnings, so again do not use E10. Have a look at Hunts Marine warning:
http://www.huntsmarine.com.au/ethanol-blends-and-boating

[joey_1987]

Yeah don't use E10 as ethanol has the potential to eat away at components which are not chemically resistant to ethanol.
Octane rating 91 should be fine it's not exactly a high compression rotary engine but premium wouldn't hurt it either. You might be wise to premix some fuel (and use a decent oil, Yamalube for a Yamaha makes sense) until you confirm that the oil injection is working. Also if you are unsure of what oil is in the oil tank then drain it as best as possible and refill it with the brand you will use. Repeat the above tests to ensure the oil injection is working as when some chemically dissimilar oil types mix they can 'gel' together and block the oil injection system (uncommon but can happen) and the system won't alarm as it is for 'low oil' when you have plenty of oil, the system just being blocked.