unleaded and super[does mixing it help]

[troy]

a few years ago i was told that some outboard mechanics were recommending to mix 75 unleaded and 25 super as the material they make gaskets out of today is not #over friendly with unleaded fuel.
could this be right.
troy

[PinHead]

It does not matter..you cannot buy super petrol anymore..only lead replacement fuel.

[matthill80]

hey troy my mechanic told me that by mixing the 2 fuels you get alot higher octane rating therefore increased power. only downside is that the engine will run much hotter possibly causing damage

[drb]

sounds like an urban myth to me.

Do you really think a manufacturer would make an outboard to run on unleaded and then deliberately use gaskets that are not suitable for unleaded fuel?

Geez the warranty claims would send them broke pretty quick

In my book use what the manufacturer recommends. If you want more power buy a bigger engine.

[Billo]

some funny myths out there.....i am no mechanic , so i cannot prove or disprove any !

One interesting one is the amount of people i have seen using premium unleaded with a premix 2 stroke style engine as ' premium is better for your eingine ' .

From what i have been told , premium does not carry oil very well at all , and oil will sit at the bottom of the fuel tank , hence running at huge temps on a full tank , then blocking up when the tank is running towards empty as the oil starts getting picked up.

advise i have says premium is very effective for oil injected motors though ....but dangerous if your pre mixing .,.

can anyone confirm or deny this ?

[anthony_love]

I tend to use premium fuels in my current rig - a 30hp premix yamaha. I've never had a problem.

The reason I use premium is that it seems to store a fraction longer for me, as I don't use much fuel and most of my trolling is done using the Minn Kota up front.

I think you'll find that driving to the ramp will mix the oil in with the fuel pretty well through natural agitation.

[troy]

matthill 80 i just tracted down a friend of mine who was actually told to do this by the dealer he bought it off.
as i said i was a few years ago actually[ 8 ]he had a yamaha and it is still going fine.
he also said the fuel lasted a lot longer..
troy.
i am only saying what i was told

[CHRIS_aka_GWH]

do outboards have catalytic convertors ?

[anthony_love]

An unequivocal "no" :-)

[blaze]

welcome to ausfish Anthony
cheers
blaze

[troy]

yes anthony welcome to the site.
troy

[youngfisho]

I use PULP in my outboard (70hp Johno Oil injected 99) every now and then. Because it is a cleaner burning fuel then the weaker 91 octane brew, it is better for your engine, reduces carbon build up and also improves the acceleration especially in higher reving engines such as four strokes. It should not make your motor run hotter, as the fuel is being burnt more efficiently. It really depends on the size of your wallet. I run optimax in my car as I can tell when an inferior fuel is being used. The car is sluggish and struggles more when reaching higher rpm. the same comparision can be made with outboards. Decreased performance due to decreased combustion. If only PULP was as cheap as regular unleaded.

andrew

[NQCairns]

Anecdotal evidence from the weekend lake go fast guys with exhaust gas temp gauges in the US is that the higher pump octane is raising their combustion temperature outside of older fuels (and the US has higher quality fuels than here staight from the pump). This has been put down to fuels now using oxygenates to increase octane, today I very much doubt any go fast guys etc would trust their expensive engines to Australia's third world quality fuels even the ones with extra additives, if all you have got is a mud base to make a cake and you add enough flavours and colours someone would eat it.
I wouldn't have a problem adding 1/4 to a tank.