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Thread: 300xs avgas?

  1. #1
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    300xs avgas?

    California 91 octane fuel is terrible out here and goes bad quickly, I want the safest option for my 300xs. Is 100LL octane avgas ok for 300xs? Any issues with it? I heard it’s the cleanest and lasts the longest, low carbon build up and cleaner for injectors.

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    Stay away from lead.

    Buy toluene to mix with the gas, or buy lead free race fuel.

    Avgas is also hard on piston rings, but that is a secondary consideration.

    Here is a good old thread:
    https://www.screamandfly.com/showthr...uot-dirty-quot
    __PRESENT
    Markus' Performance Boating Links:
    www.toastedmarshmallow.com/performance

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    I don't think you'd have a terrible issue with it, especially with splashing 91. I ran it for years with no side effects or issues other than it needed slightly different jetting or ecu setting than 110 race fuel in a 185 psi motor. It will certainly be safer than a load of crap pump gas.

    There is this too, https://www.pure-gas.org/index.jsp?stateprov=CA but you are at the mercy of what on the list is actually in the tanks.

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    Quote Originally Posted by Markus View Post
    Stay away from lead.

    Buy toluene to mix with the gas, or buy lead free race fuel.

    Avgas is also hard on piston rings, but that is a secondary consideration.

    Here is a good old thread:
    https://www.screamandfly.com/showthr...uot-dirty-quot
    __PRESENT
    Whats wrong with lead?

    Merc used used to mandate it for race engines.
    Was used in F1 till recently.
    Its reliable and it stores well.
    Last edited by powerabout; 01-22-2020 at 08:04 AM.

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    I ran it for years in outboards...good compromise between crappy pump gas and all out race fuel...

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  7. #6
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    Quote Originally Posted by powerabout View Post
    Whats wrong with lead?

    Merc used used to mandate it for race engines.
    Was used in F1 till recently.
    Its reliable and it stores well.
    The motor will love it ...

    Indoctrinated tree huggers, not so much ....



    The blank stare tell's me this one ate way too much leaded paint as a child ...


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    This study provides the first evidence that progressive and ongoing decline in cognitive function, particularly functions such as learning and memory, is associated with adult lead exposure long after exposure ceases.

    People who have worked in jobs with high levels of lead exposure are up to 3.4 times more likely to develop Alzheimer's disease, an incurable and fatal degeneration of the brain that causes dementia, the researchers told a meeting of the American Academy of Neurology in San Diego. Lead causes brain damage, and strict controls have been placed on lead in paint and in gasoline because of it. But most concerns have centered on its effects in children.

    The relationship between performance on cognitive tasks and circulating levels of lead in blood and accumulated levels of lead in bone was examined in 141 middle-aged and elderly men. Men with higher levels of blood and bone (tibia) lead copied spatial figures less accurately; men with higher levels of bone (tibia) lead had slower responses for pattern memory. These findings suggest that low levels of lead contribute to impairments in cognitive function among elderly men.
    Studies have also shown that lead exposure could cause age-related cataracts, the leading cause of blindness and visual impairment worldwide, writes Schaumberg.
    https://www.webmd.com/eye-health/new...-for-cataracts

    Sad to see so many people handling leaded race gas without any protection. Although, the dumber they get... the easier they should be to beat!

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    As I remember like 20 years ago reading Power boat mag that a lot of cali guys were running av gas in there BB O/S boats as it was cheaper out there than 91 oct when you take the road tax off and readly available . If i remember right they were dumping like a pint of O/B 2 stroke oil in to every 50 gals for there BB.

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    We ran hundreds of gallons of 100LL through our 300 Promax's on a 28 Skater. We had stock tanks and the ethanol at 10% was eating them up. No non ethanol fuel in Md. in the area we lived so at that time Avgas was our only option. Plus back then the cost was about the same as 92 octane at the pump.
    There are those that say you will sacrifice some performance by using a higher octane than needed but we really never noticed that. That you sould rejet or have the ecm remapped, we just ran them as is and they had close to 500 hrs on them when we sold the boat and still running strong.

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    I don't think anyone will argue over how bad the lead is for you... I have run it in most everything 2 stroke powered and never seen any detrimental effects not even the lead build up on sparkplugs like in the aircraft engines but I tend to change plugs a lot. I did some reading on avgas back in 05 because the epa was hot on getting it banned and I was maintaining/flying a huges 300C helicopter which had the highest compression pistons Lycoming made and at the time several companies said they were and very close to having unleaded UL100 avgas but it may not work for certain engines?... Here we are 15yrs later and no unleaded kinda hard to believe.
    Last edited by H2OPERF; 01-22-2020 at 04:13 PM.

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    Quote Originally Posted by David - WI View Post


    https://www.webmd.com/eye-health/new...-for-cataracts

    These findings suggest that
    low levels of lead contribute to impairments in cognitive function
    among elderly men.

    Studies have also shown that lead exposure could cause age-related cataracts,


    Sad to see so many people handling leaded race gas without any protection. Although, the dumber they get... the easier they should be to beat!
    Suggest ... Could ... The elderly ... age-related ...

    I've lived long enough to "suggest" that you "could" pour it in the tank, instead of drink it yourself. And you too might live long enough to become an "elderly" old man ...
    Race against many 70 to 95 year old men ... do ya .. ???
    Those would be some "races" you could be proud of ...


    Markus
    https://www.wired.com/2013/01/looney...t-sad-history/

    Markie-Mark, Ifin ya ever get a job in Chernobyl or an Anthrax factory, ya might not wanna eat or snort any of that stuff you find inside ....
    Also comrad, wear condom, preferably American made ...

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    Its supposed to go on the tank...yore not supposed to soak your balls in it.

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    If you consider how dumb young people are today I am starting to think lead exposure helped our generation.

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    Hate to think about how much gas I tasted siphoning gas when I was a kid...

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