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ted@theted. ted@theted. is offline
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First recorded activity by BoatBanter: Oct 2010
Posts: 8
Default mixing gas and oil questions

On Mon, 25 Oct 2010 13:13:49 -0400, "Flying Pig"
wrote:

"Steve Lusardi" wrote in message
...
Ted,
Adding lube oil to gasoline lowers the flash point of the fuel increasing
the chance of detonation. Oil in the fuel is necessary for these type of
engines, but NEVER use more than the manufacturer's recommendation.
Failure to follow this simple direction could melt the pistons, the heads
and effectively ruin the engine and I have seen this hundreds of times. I
know this is counter intuitive, hence the number of times this failure
occurs.
Steve



Interesting. The Outboard Shop, the local evinrude/johnson dealer, gave me
the exact opposite recommendation. The question came up with my newer engine
which is designed to run on 100-1 mix. They told me it will run just fine
on the same stuff as my older engine, a 50-1 mix. They also cautioned me
that the least "too-little" mix , such as missing by a bit when filling from
a not-empty supply and having to guess at the right amount, could turn it
into an anchor. Failure to use enough deprives the engine of its
lubrication, and things seize up.


when the evinrude was re-built the mechanic told me to mix 50-1
instead of the regular 25-1 until it got broken in. when i asked
if it would hurt to keep mixing it that way all the time he said
no.

Further, my manuals for both engines show to use double the oil in severe
use conditions. I.e., in the newer one, 50-1, in the older one, 25-1. More
oil, at least as inferred from the manuals, assures that won't happen, even
if you overdo it.

I grant you that quadrupling the oil may have some deletorious effects, but
my common sense tells me that 16% more than specified as ADEQUATE should not
be a problem.


that mechanic and the jetski mechanic both said too much is okay
but too little will ruin the engine because what you're doing is
running it low on oil, which certainly makes sense.

Also, I've never seen oil being more subject to explosion/flash than
gasoline. How does adding oil to fuel make it more volatile?


for real. i've been running the evinrude about 50-1 for about a
year and it hasn't blown up or even overheated. one person told
me that mixing too much oil makes it have a problem with wanting
to quit when you're trying to start it...it will fire up for a
few seconds and then die which it is doing. but he may have just
said that because he knew i was mixing it heavy on oil. he told
me that at a time when we were having the problem. it usually
only does it once or twice though, and then runs fine.