Stock Outboard Gas?

[Hydroglobe17J]

Hello anyone, I hear gas could be a problem at the stock races. Can anyone help me with which gas to purchase?,Exxon any good? Do you need airplane gas or High Test Premium?
I would really be thankful if someone could steer me in the right direction.
Thank You,
Times have changed!

[Bill Huson]

fuel is tested . . .

Pump gas means gas from a gas station. Winter gas with those *additives* can be a problem but any gas WITHOUT ethanol/methanol in the mix is good. OIL is the problem. Some high performance 2-stroke oils will give the fuel check meter a stroke! I never had a problem with standard TCW-III oils. (Merc/Yamaha)

Octane is motor dependant. My 15ci Hot Rods were pumping 195 psi compression, so I used high test fuel, but used regular 86/87 octane in the OMC A motors.

[DougMc]

Octane is motor dependant. My 15ci Hot Rods were pumping 195 psi compression, so I used high test fuel, but used regular 86/87 octane in the OMC A motors.

What does that mean in desk-jockey terms? Why high test in the Hot Rod, but regular in the OMC?

What would you use in a Yamato 102?

[Joe J]

[QUOTE=Bill Huson]Pump gas means gas from a gas station. QUOTE]

Av-Gas comes out of a pump.

Joe

[Bill Huson]

compression ratio . . .

high compression engines use high test/octane gas. Low compression engines use low test. The Hot Rod had high compression, OMC low. Methinks the OMC was 8:1 on a good day. compression tested around 135 psi compared to the HR 195 psi. A low compression engine will run on high test, but only testing on the course will determine if that's an advantage, and I doubt it is. A high compression engine will run of low test but probably not well, and preignition may roast a piston or two.

Look at cars. Your basic car has about 8:1 compression ratio and the specifiys 86/87 gas. Sporty cars with mega-horsepower and a gazillion vales per cylinder may have compression ratios around 11:1 and specify 96 octane. This number is usually on your gas cap. Most engine experts say buying high test for a car that doesn't need it is a waste of $$$. I agree.

I seem to recall the Yamatos are also around 8:1 or 8.5:1. I ran regular gas in mine witha 25:1 oil mix. Check the pit scuttlebutt `cause methinks the oil mix ratio has changed.

[Bill Huson]

Yes, av gas is *pumped* . . .

and I'm sure many stock outboarders have cited that in their defense when busted for *smoked* gas. If you've managed to tweak the compression ratio to the Big Squeeze, than I imagine av gas would be helpful, but av gas in an engine that's pumping an 8:1 or even a 9:1 compression ratio is just emptying your wallet faster.

I doubt av gas would top the test meter, but usually folsk who buy av gas are also fiddling with *hot* oil mixes and that will pop a DQ on the meter real quick. I recall Johnson GT oil - popular with bass boaters - made the meter shout out DQ!

[Joe J]

Actually in California some of us are using it simply to pass the meter. I fully understand that the compression ratio is too low to take advantage of the octane. The problem is our state has so much CRAP in our gas that the meter jumps, espically after adding 2 stroke oil.

To me, the rule about gas coming out of a pump is unenforceable.

Joe

and I'm sure many stock outboarders have cited that in their defense when busted for *smoked* gas. If you've managed to tweak the compression ratio to the Big Squeeze, than I imagine av gas would be helpful, but av gas in an engine that's pumping an 8:1 or even a 9:1 compression ratio is just emptying your wallet faster.

I doubt av gas would top the test meter, but usually folsk who buy av gas are also fiddling with *hot* oil mixes and that will pop a DQ on the meter real quick. I recall Johnson GT oil - popular with bass boaters - made the meter shout out DQ!

[sam]

Hello anyone, I hear gas could be a problem at the stock races. Can anyone help me with which gas to purchase?,Exxon any good? Do you need airplane gas or High Test Premium?
I would really be thankful if someone could steer me in the right direction.
Thank You,
Times have changed!

Regular gas from the closest gas station works fine in the A motors. I do not recall any incidences in the east where local gas wasn't declared legal before a race. It should work well in C's too.

The cranking compression in my tightest FE motor is 275# (14:1?) I use AV gas in it with Klotz Super Techniplate oil and it always passes the fuel meter test. If you aren't in the ultra high compression range, Bill is right ... all AV gas or racing gas is doing is emptying your wallet faster

[Bill Huson]

Ah yes, California . . .

CA - we try to keep our air clean, but DON`T breath the fumes when you're fueling your car `cause that crap will kill you! Sorta like the fish-safe special bottom paint for aluminum boats. Good for the fishies but so freaking toxic you have to have it *professionally* applied by a painter in a full hazmat body suit with piped in breathing air.

Wintertime on the east coast MTE something is added to the gas. Stinky stuff, and bad for the test meter.

Sam: Yes, east coast gasolene has failed the test meter at times. I think it was Shell who added like 10% alcohol to their premium fuel, and that caught a few racers by surprise. Lesson: Read the label of the gas pump before filling up.

[Abbott Racing]

That brings up a good question on gas legality. I brought fuel form home (tested before we left) and when we got to Dayton fuel was illegal. Went to a local station got some gas and gas tested borderline. The guy testing my gas said I should use Cam2 or Blue Streak??? racing fuel like most of the guys and there is no problem.

I also took the time to ask a few guys who were sporting the decals of these fuels and sure enough they were using it and it passed.

Is this stuff really legal if we use the term Pump gas, you can't go to any station and get this type of fuel.

Don't mean to stir up controversy, just curious to hear some feedback...

[Fast Freddie]

Racing Gasoline

In Wisconsin there are service stations that sell racing gasoline from pumps. Road octane no. ~110, leaded, passes fuel meter test without worry (same number as the setting number for the Digatron).

Of course the rule that says the fuel must be standard pump gasoline is unenforceable! There is no standard pump gasoline. There are many variations on what you buy for your car. That rule also would make straight gasoline illegal the way it is written - you MUST have oil mixed in the fuel to be legal under the written rule! What happens in the future when (if) we have 4-strokes?

I used to think it was a waste of money to use racing gas in the stock engines because these engines do not need the additional octane. However, after throwing away a few cans of gasoline with expensive synthetic oil mixed in because it failed the test, it turns out the racing gasoline is cheaper on average.

Another problem sometimes encountered is that a little water in the gasoline causes it to fail the meter test. So, drain your tanks and keep your fuel cans sealed tight so it doesn't pick up atmospheric moisture (or rain water).

Mike Wienandt, OPC Chair, will have a seminar concerning gasoline rules on the Wednesday before the APBA National Meeting in Ft. Lauderdale. Might be an educational experience!

Good Luck,

Fred

[Bill Huson]

Another way to fail the test . . .

For some not known to me reason, storing mixed gas in your basic plastic fuel container effected the readings I was getting. Fresh mix, good to go. End of day after cooking in the storage container, reading was significantly higher. I never actually flunked the dipstick tester but came quite close. after that I mixed enough gas/oil for the day and kept the storage tank in the shade.

[Hydroglobe17J]

Thank You Everyone for your input!
Earl

[raceboat61-S]

Gents,
Aviation 100Low Lead fuel is illegal for Stock Outboard racing. Too bad, too because it is very federally controlled, uniformly blended, and usually available anywhere in the world.
I am NOT an engineer but in a conversation with a fine old racer from the 60's he told me that in our older deflector-type engines high octane is a power robber. He contended that there are significant differences between the octane requirements of a high performance 4-cycle and a medium performance 2-cycle. The addition of octane additives is to slow the combustion of straight gasoline so that the explosion is extended to the full length of the 4-strokes power stroke. By design it produces power until the exhaust valve is opened at the bottom of the crank stroke. In a 2 cycle the power must be extracted before the piston reaches the exhaust port which may be only at one-half of the pistons travel. In my mind I want a short, violent explosion even if it is incomplete and not very fuel efficient because I want all the work done before the gases start leaving through the exhaust port. I don't want high octane regardless of my compression. I welcome your ideas, guys. Mike Marshall Raceboat61-S

[Joe J]

How can you say it's illegal? The rule as it is written cannot be enforced. Plus, it does come out of a pump, a Chevron pump in my case, to be exact.

Joe

Gents,
Aviation 100Low Lead fuel is illegal for Stock Outboard racing. Too bad, too because it is very federally controlled, uniformly blended, and usually available anywhere in the world.
I am NOT an engineer but in a conversation with a fine old racer from the 60's he told me that in our older deflector-type engines high octane is a power robber. He contended that there are significant differences between the octane requirements of a high performance 4-cycle and a medium performance 2-cycle. The addition of octane additives is to slow the combustion of straight gasoline so that the explosion is extended to the full length of the 4-strokes power stroke. By design it produces power until the exhaust valve is opened at the bottom of the crank stroke. In a 2 cycle the power must be extracted before the piston reaches the exhaust port which may be only at one-half of the pistons travel. In my mind I want a short, violent explosion even if it is incomplete and not very fuel efficient because I want all the work done before the gases start leaving through the exhaust port. I don't want high octane regardless of my compression. I welcome your ideas, guys. Mike Marshall Raceboat61-S