"Rick Morel" wrote in message
...
My 2-cents.
snip.............
.. Heck, I remember one guy that used 12.5-1 (2
qts. in 6 gallons) in his ultralight. Looked like he had a smoke
system!
snip...........
Rick

Got that beat.
My 1954 British Seagull 40 Plus uses 10:1 ratio.
If there's a strong tail wind, I almost choke to death, so I constantly gybe
to keep the blue exhaust smoke on one side or the other.
BTW I don't use that engine much anymore.

On 10/25/10 8:41 PM, YukonBound wrote:


"Rick Morel" wrote in message
...
My 2-cents.
snip.............
. Heck, I remember one guy that used 12.5-1 (2
qts. in 6 gallons) in his ultralight. Looked like he had a smoke
system!
snip...........
Rick

Got that beat.
My 1954 British Seagull 40 Plus uses 10:1 ratio.
If there's a strong tail wind, I almost choke to death, so I constantly
gybe to keep the blue exhaust smoke on one side or the other.
BTW I don't use that engine much anymore.


In 1954, I recall my dad letting me have a 7.5 hp Evinrude Fleetwin on a
12' Skimmar brand skiff. The boat actually planed. Half pint of oil to a
gallon of gas.

On Mon, 25 Oct 2010 18:48:23 -0500, Rick Morel
wrote:

Not water cooled, but a real world example. About 20 years ago I built
and flew a gyrocopter. It used a WW II era 90HP, 4 cylinder engine.
The manufacgturer's recommended mix was 25 parts 130 Octane leaded
aviation gas to 1 part 40 wt. aviation (mineral) oil.

Interesting! Do you happen to know Ken Brock? He was one of the
gyrocopter pioneers and flew one across country for the publicity.
He and I appeared together on a television show called "To Tell The
Truth" back in the early 70s. I was one of his "imposters" and Ken
of course was the real thing.

Wilbur,
You have it almost correct, but what actually happens is that in the hottest point in the combustion chamber, the fuel/oil mix
diesels starting a flame front, but before that flame propagates across the piston surface, the spark sets off another flame
front. When the two fronts collide there is a very high temperature explosion that causes the aluminum to actually melt. This can
be heard as a knock, but it is very difficult to hear in an outboard engine. At low throttle, this can be tolerated for a few
seconds, but at high throttle, it is almost instantaneously terminal, as much of the head and piston blows out the exhaust port as
molten aluminum. The entire point of this thread is to point out that lube oil will lower the auto ignition point of the fuel
charge. Catastrophic damage, on the other hand is a product of chamber temperature, fuel/air ratio, as well as the fuel mix
tolerance to auto ignition. If the engine is of the low performance variety, fuel/oil mix tolerance will be greater, but in a high
performance configuration much more attention must be given to the fuel mix.

Historically, the migration from the recommendation of 25:1 to 50:1 occurred with the change from plain bearings to roller/needle
bearings. Oil injectors allow even more reduction, because lubrication can be assured at low throttle settings where lube
starvation always occurs with premix fuel. This lube starvation was the primary driver for fat fuel/oil mixes.
Steve

"Wilbur Hubbard" wrote in message anews.com...
"Bob" wrote in message ...
WARNING WARNING WARNING WARNING WARNING WARNING
WARNING WARNING WARNING WARNING WARNING WARNING
WARNING WARNING WARNING WARNING WARNING WARNING
WARNING WARNING WARNING WARNING WARNING WARNING

Interesting. The Outboard Shop, the local evinrude/johnson dealer, gave me
the exact opposite recommendation.......

Fact: people forget 50% of what they hear immediatly.
In other words SKip you probablly heard, "bla bla bla recomend bla bla
evenrude bla..."

Further, my manuals for both engines show ........

Gaaaaa you have to comprehend also my selective reader.

I grant you that quadrupling the oil may have some deletorious effects, but
my common sense tells me........ should not be a problem.

Hey sikp have you been using your BrontoThesaurus again ? Please dont
use such big words as deletorius. They sont have a Salubrious effects
on my comprehension.

Also, I've never seen oil being more subject to explosion/flash than
gasoline.

How does adding oil to fuel make it more volatile?
L8R
Skip

:: Your comment and question shows a basic lack of fuel and combustion
:: concept understanding. Will those here more knowledgable please
:: inlighten SKip. Im off to watch the 30 foot 17 second swells hit the
:: jetty.


I think Mr. Grundlach may be correct for once. Adding more oil to a given amount of gasoline actually acts as an anti-knock
ingredient. It lowers the rate of speed at which the flame front propagates from source of ignition (spark plug) to
cylinder/piston surfaces.

It increases the duration of the burn and thus lowers the temperature of the burn. Add too much oil and the motor will run as if
the choke were on. I don't know of any cases where piston damage from heat will result. The worst that will happen is the works
(piston rings piston crown) might become gummed up, the exhaust port will become carboned up and exhaust gass passage restricted
and exhaust port opening retarded because the piston will have to travel down several millimeters more before it reaches the
exhaust port opening. I have seen exhaust ports so carboned shut that one could barely poke a finger through it. The engine
would not rev up and it performed like the choke was on all the time.

Too much oil is, indeed, a bad idea but not for the reasons you listed.

Wilbur Hubbard
(worked as a two-stroke mechanic for seven years and as a technical advisor for a Japanese motorcycle company for seven years)

On Mon, 25 Oct 2010 22:30:42 -0400, Wayne.B
wrote:

On Mon, 25 Oct 2010 18:48:23 -0500, Rick Morel
wrote:

Not water cooled, but a real world example. About 20 years ago I built
and flew a gyrocopter....

Interesting! Do you happen to know Ken Brock? He was one of the
gyrocopter pioneers and flew one across country for the publicity.
He and I appeared together on a television show called "To Tell The
Truth" back in the early 70s. I was one of his "imposters" and Ken
of course was the real thing.

No, but I did meet him. A great guy. About all the gyrocopters used
his horizontal stabilizer and control system.

Rick

"Wilbur Hubbard" wrote in message
anews.com...
ted@theted. wrote in message
...
On Mon, 25 Oct 2010 11:46:00 -0700 (PDT), jamesgangnc
wrote:

On Oct 25, 12:02 pm, ted@theted. wrote:
i have a jetski and a boat with an evinrude 115 hp outboard. can
they both use the same gas/oil mix? someone told me it should be
a pint to six gallons but i would rather mix a pint with 5
gallons because it's easier and to be on the safe side if that's
ok. is a pint to 5 gallons ok for both the jetski and the
evinrude?

thanks!

ted

I only have smaller 2 strokes and one jetski. The jetski mixes it's
self with a oil pump to the carbs.

the guy who was working on it suggested that i have the pump mix
system removed for a couple of reasons. one was because it was
smoking badly meaning it was mixing too much oil, and the other
was because somewhere in that system it was leaking oil into the
hull. he said it could just as easily mix too little as mix too
much and that would ruin the engine, so i figured after getting
lucky and having a second chance it was best to have the messy
threat removed so it won't ever be an issue again.

But I mix the same ratio for all
my small engines without any problems.

what ratio?



Idiot! Moron. Fool. There could well be other oil feed lines than the ones
to the carbs that you see. That might be where the oil leak is coming
from. If this were the case and the oil feed was going to lubricate the
crankshaft main bearings, for example, and there were oil seals in place
to separate the bearings from the crankcase to better facilitate secondary
compression and transfer of the fuel/oil mix, the main bearings, having no
source of lubrication, (the fuel/oil mixture couldn't get to the bearings
because of the seals) would quickly overheat and fail. your mechanic is
not to be trusted. He's stupid, ignorant or both.

Wilbur Hubbard
Sounds like Wilber is off his meds again. Just let him ramble.

"YukonBound" wrote in message
...


ted@theted. wrote in message
...
i have a jetski and a boat with an evinrude 115 hp outboard. can
they both use the same gas/oil mix? someone told me it should be
a pint to six gallons but i would rather mix a pint with 5
gallons because it's easier and to be on the safe side if that's
ok. is a pint to 5 gallons ok for both the jetski and the
evinrude?

thanks!

ted

I follow the manual recommendations.
i also dropped into the Vespa scooter store and bought the little plastic
measuring device.
It's great for a 50:1 mix. Saves guess work when out on the high seas.
You take a Vespa out on the high seas Don?

"YukonBound" wrote in message
...


"Rick Morel" wrote in message
...
My 2-cents.
snip.............
. Heck, I remember one guy that used 12.5-1 (2
qts. in 6 gallons) in his ultralight. Looked like he had a smoke
system!
snip...........
Rick

Got that beat.
My 1954 British Seagull 40 Plus uses 10:1 ratio.
If there's a strong tail wind, I almost choke to death, so I constantly
gybe to keep the blue exhaust smoke on one side or the other.
BTW I don't use that engine much anymore.
Helps to keep the mosquitoes away I'll bet?

"MMC" wrote in message
g.com...


"YukonBound" wrote in message
...


ted@theted. wrote in message
...
i have a jetski and a boat with an evinrude 115 hp outboard. can
they both use the same gas/oil mix? someone told me it should be
a pint to six gallons but i would rather mix a pint with 5
gallons because it's easier and to be on the safe side if that's
ok. is a pint to 5 gallons ok for both the jetski and the
evinrude?

thanks!

ted

I follow the manual recommendations.
i also dropped into the Vespa scooter store and bought the little plastic
measuring device.
It's great for a 50:1 mix. Saves guess work when out on the high seas.
You take a Vespa out on the high seas Don?

Why not... strap a couple of pontoons on the side and engage the marine
drive..............................

On 10/26/10 10:19 AM, YukonBound wrote:


"MMC" wrote in message
g.com...


"YukonBound" wrote in message
...


ted@theted. wrote in message
...
i have a jetski and a boat with an evinrude 115 hp outboard. can
they both use the same gas/oil mix? someone told me it should be
a pint to six gallons but i would rather mix a pint with 5
gallons because it's easier and to be on the safe side if that's
ok. is a pint to 5 gallons ok for both the jetski and the
evinrude?

thanks!

ted

I follow the manual recommendations.
i also dropped into the Vespa scooter store and bought the little
plastic measuring device.
It's great for a 50:1 mix. Saves guess work when out on the high seas.
You take a Vespa out on the high seas Don?

Why not... strap a couple of pontoons on the side and engage the marine
drive..............................


A VespaSki, to be seen in the next Bond move. Don Bond driving, Scarlett
Johannsen in the passenger seat.