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Discussion Starter · #1 ·
During the summer months, I run mid grade gas in my 200 ox66 yamaha. Now that cooler weather is here, will it help to run high test. The motor usually turns over on the first try during warm weather, but may take 4 or 5 trys on colder days. Thanks, 5th (Marty)
 

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Octane is a rating on how the gas burns.It really does not have to do with power.The low octane fuels burn at much wider temperature range.The higher octanes burn at a much tighter range.
That is the only big differance.There is other additives but nothing that would help an older motor.

Hard starting in cold weather is often the fuel/air mixture.Cold air is more dense then warm air.

You can try to advance the throttle about 1/3 of the way (indent button) and see if that helps.Be sure to bring it back to idle once the motor starts.

Some motors require the throttle to be advanced 2-3 times (back/forth) while starting.If it still gives you trouble- you might need to make an adjustment inside the motor but then you'll need to reset it come warmer weather.Most times advancing the throttle will do the trick.If you can-start the motor once a week at home.The more a motor is ran-the better it starts :thumbup:.
 

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I advance throttle a bit, push key in to choke, motor starts in 3 seconds.

When cold I usually have to press the key in a couple times after it starts to choke it because she starts to die out, in 30 seconds or so it's fine and I let her warm up.

It's an 02 carbed yamaha 150, would think it has an auto choke for when it starts.

TIGHT LINES!!
 

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Discussion Starter · #4 ·
Thanks guys; I really can't say it's "hard" starting when it turns over in 4-5 tries; but I was just curious if the higher octane would assist in starting. I guess I'll save a few pennies and continue the mid grade gas.
I run "startron" in every tank; but would you think it would be benificial to begin adding the marine "stabil" now while I run through December?
5th (Marty)
 

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I too use Statron in the winter months, full bottle on every fill (60gal tank) just because I don't use the boat as much.

From the information I've read, you don't need both startron and Stabil. Startron uses enzymes in a petroleum product to help break down water and keep fuel "fresh"

Stabil, from what I've read, uses a chemical mix to do this.

i.e. they both keep the fuel fresh.

Startron also touts it's ability to help reduce carbon deposits, Stabil, from what I've read, only helps to stabilize the fuel for storage.

I had a bottle of stabil sitting in my garage for 3 months, all kinds of red gunk accumulated on the bottom, whether accurate or not, I did not think something that gunked up like that would be good for my fuel system.
 

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The octane rating of gasoline tells you how much the fuel can be compressed before it spontaneously ignites. When gas ignites by compression rather than because of the spark from the spark plug, it causes knocking in the engine. Knocking can damage an engine, so it is not something you want to have happening.

Additive wise, I don’t use anything on a regular basis. I only usee Stabil during the winter when I'm not sure when I'll get out the next time.

Otherwise I keep an eye on the fuel in your Racor and use additives as required. If you start seeing “cloudy” fuel or are getting water in the filter on a regular basis its time to add the recommended dose of Startron and fresh fuel into the mix.

This year I started keeping a ½ tank of fuel onboard and replaced what I used the next time out. This kept fresh fuel in the mix and totally eliminated what little moisture problems I had last year.
 

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A mechanic once showed me a big bucket full of burned outboard motor pistons. He said it was from burning high test in motors designed for 87 octane. I do not know if that was true or not but he was surely convinced it was. I would be careful about using octane other than what is recommended by the manufacturer. It is a waste of money and may do some damage.
 

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and to your original question, I only use 87 in my rig based on a recomendation on another board form a boat guy who's opinion I trust

"Fresh fuel....87 Octane, not 89 or 93 octane. Higher octane fuel doesn't burn completely in engine's with compression ratio's of 5-6 to 1 which is what most outboards have.... "
 

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Discussion Starter · #9 ·
Thanks for all the replies. As a real novice, I was thinking just the opposite from what's discussed on the posts. I thought if I upped the octane the gas would "fire" quicker and burn "cleaner" during the winter months. I assumed it would also reduce the amount of carbon "left behind" on the plugs and O2 sensor. Since it ran well all summer on mid grade 89 octane, I guess I will continue its use this winter. Instead of "helping" the motor, I may be doing just the opposite. I remember back in the 70's when some of the "muscle" cars with big motors would "ping" on lower octane gas. Some wouldn't even quit running when you turned off the key. I guess the old addage "if it aint broke, don't fix it" works in this case. Thanks, 5th
 

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You should be using Ring Free each fill up.Very important for long engine life.

Star Tron is also good to use.The new E-10 fuel can break down over winter and lose octane.Star Tron helps keep the gas fresh.

We are basically putting back what is taken out of gasoline :rolleyes::rolleyes:. Cars/trucks use fuel much quicker/smaller tanks and do not suffer like boats do.
 
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