Picked up my mates new boat on Saturday and the question was ask of the mechanic premium or unleaded mechanics reply normal pump fuel not sure of reason why. Mate has always used premium in everything he has owned so he thought it was needed. Mick King
Yes Avgas does have lead, even though they say it's low lead.
But I guess if you can't use it, then Bummer.
If your in to experimenting with fuel try camphor balls or moth balls soaked until they disolve.
You get quite interesting results from that, but for the regular punter don't try it, unless your in to rebuilding motors.
Last edited by Roughasguts; 18-02-2007 at 10:46 PM.
It is an interesting thread, and a lot of concern about how long the fuel stays in tanks, which is valid by the looks of things.. Can I please ask, how does this differ from the time the fuel spends in the tanks at the servo, or at the oil company ?
Is it just that it is fresher coming from the supply, or is it because you generally have a greater volume in the servo tanks etc ?
Having worked in a large servo for quite a few years, i can tell you the fuel doesn't stay in the tanks very long. We used to sell or empty the tanks at least twice a week, sometimes 3 times depending on seasonal fuel sales. In comparison to some people who don't get out in their boat more than 3 or 4 times a year there is big concern for fuel tanks containing water.Originally Posted by Dirtysanchez
The time the fuel sits in storage prior to this I have no idea.
I always use regular unleaded in my new 115 HP 4 stroke merc.
Not enough time in the day, to many spots to fish!
I will use only unleaded in my 89, 90hp engine because it needs nothing more any increase in octane will go straight out the exhaust also the additives needed to control the artificial way they increased the octane rating are not considered best for use in a 2 stroke.
I will occasionally top up with premuim (like 1/3 max) to make myself feel better if the tank fuel may be a little old but still young enough to use, although I will never use undiluted premium by choice.
cheers fnq
Doesn't anyone read their factory motor manuals? Both my Yammy 2s and Suzie 4s manuals specifically insist on ULP. No point paying a premium for a fuel that is not recommended by the manufacturer. Claiming "better economy" using PULP in an outboard is an urban myth.
As for "old fuel", I'm much more concerned about buying dirty fuel. Top up with new stuff regularly and have a quality fuel filter.
according to the BP website (and shell I think) they say their fuels are good for at least 3 months storage. I wouldnt be keen to test this theory on the water.
Once upon a time we used a fuel called STANDARD in all two strokes. Makes you wonder doesn't it!! It was no good because the lead in it...the lubricant...made you DUMB
Now we have unleaded....which they say is carsenojenic
As Simon Towsend would say "The world really is wondeful"
BilgeBoy
I understand two stroke mix oil/fuel effects the octane rating of the fuel. Why bother going to PULP in a two stroke? Even the oil injected type 2s would have the octane rating change due to the oil.
Many of the VMRs/Coast Guard run PULP in their 4s Outboards. I think this is more of the case of getting that marginal difference in performance for tight situations.
Other than the above, for my own preference I run ULP. It is as recommended and works satisfactorily (91 octane).
Just keep the fuel fresh. Found out the hard way with old fuel.
Cheers
John
Does make you wonder, a vehicle running ULP must have a catalytic converter or hot box in the exhaust. Ain't no outboard I know has one, and it couldn't with water going through it.Once upon a time we used a fuel called STANDARD in all two strokes. Makes you wonder doesn't it!! It was no good because the lead in it...the lubricant...made you DUMB
Now we have unleaded....which they say is carsenojenic
As Simon Towsend would say "The world really is wondeful"
BilgeBoy
if you look up what the experts say on octane there are a couple of things of interest in what they say.
One is that for fuel to be 'high octane' it has to be harder to burn/explode. That's so you dont get it going bang before it should. If you use it (HO) in an engine designed for lower octane fuel you aren't going to get more power, but there is a distinct possibility that you may get less power because it hasn't burnt properly by the time the exhaust port opens.
The other one is that they point out that the high compression engine's extra power doesn't come from the high octane fuel. It comes from the higher compression. The 10:1 engine behaves like it has squeezed 10 units of mixture into the space of 1, the 8:1 as though it squeezed 8 units into 1. The high octane fuel just lets you squeeze 10 into 1 without pre-igniting from the heat before the plug fires.
To me using the fuel the engine maker says in its book that it designed the donk to use makes sense and you don't waste a lot of money buying a more expensive fuel that gives you no return for the extra cost.
Little Jim has a point LPG the gas you put in your car has a Higher Octane rating than PULP around 120 plus Octane rating. But to get any benefit from that fuel you need to run 20.1 but I guess we use it cause it's cheaper. And probably a better alternative to ethanol.
so what if you can only get fuel at a BP its either ethanol or pulp?
thats my choice early in the morning. I go with the pulp
Ethanol or PULP? Gee they don't give you much options. That makes life very difficult.
Ethanol is going to be a whole new nightmare for boats all by itself without any of the octane issues.
is there much differance between 91 and 95
Posting Permissions
Reply With Quote
