HIGH TEST GAS

[awm]

Im a big believer in high octane gas and may
have posted about it. The reason for this post
is that i have a friend who rents honda powered
equipment. He says absolutly no high test in
honda engines.So i stand corrected. Input
anyone.

[BUSHMASTER]

most of the small engine maufac. recondmend low grade and because thats what there set up for,High octane with the price right now . i would think that it sit in the tanks long than the lower grades causeing more problems, i don't run premuim in anything i own ,with the exception of maybe going to the drag strip, an then its "purple gas".

[landscaper3]

Yeah Bush we are the same we run low octane fuel in our mowers too, If we are gonna race those mowers though I gotta run the highest octane possible to try to catch those damn dixie choppers!!

[tslawn]

I've used nothing but low octane, until..... my 25hp Kohler's muffler has decided to burn out. My dealer asked me what type of gas I was using (because of a possible warranty claim). I told him I was using at least 91 octane and he said "Good", because Kohler and/or Gravely won't warranty if I was using 87 octane because that supposedly burns out the mufflers sooner. The mower is not yet 2 years old and had 600 or so hours on it before I noticed the muffler burning out. Can anyone elaborate for me why lower and/or higher octane gas has any bearing on the muffler? May seem like a dumb question but this is greek to me (p.s. I am the wife counter-part to the business). Thanks.

[awm]

Thats where i found some info on octane and
how it works.This is how its listed on my
favorites pge.How mabe i dont know

[Runner]

tslawn, How did you know your muffler was burning out, was it getting louder? I think my Lazer EFI may be doing this.

[tslawn]

Runner, yes the muffler has gotten considerably louder. It started a couple of months ago and my husband noted it and said that he thought the muffler was burning out. Me being the penny pincher that I am said, oh it can wait. Then it kept on getting louder and louder and now I can't use the damn thing without some kind of ear protection. My dealer asked me if the muffler was white. I told them no. That it still looks the normal color but is so loud that it could blow your ear drums out. The dealer told me that if the muffler had in deed been white that they would NOT have covered it under warranty. Thankfully my dealer convinced either Gravely or Kohler that it was a warranty problem so my $260 muffler is covered. By the way, I am using a 1999 Gravely 260ZTR. What your situtaion?

[Vibe Ray]

Well, guess what guys...the octane is simply how much oil is in the gas. The higher the octane, the less amount of oil in the gas. Yes the higher octane of course burns better, but is not good for engines that do not have an efficient oiling system. It is best just to use the recommended octane gas by the manufacturer, Always listen to that if they rcommend a certain octane (it is better for the engine).

[chrisbolte]

What is with the gravely warrenty and low grade octane. I have 250 z and 3 walk behinds. Never heard anything about higher octane gas in them

[Sammy]

Oil = Octane !
Never heard that one befor.

[jaclawn]

Higher Octane=Higher Ignition point of the fuel.

If you have a high compression engine and you run the low octane fuel in it, you can have a condition known as pre-ignition. What happens, (in a nutshell) is that when the piston is coming up on the compression stroke, the heat from the compression of the fuel/air mixture gets hot enough to ignite the fuel. Your "explosion" takes place before the spark plug fires. You will hear a kockin' and a pingin'. You can also experience a condition known as "deiseling". This is when you shut the engine off, and it still "runs". The ignition system is not sending a charge to the spark plug, but the heat from the compression is igniting that fuel in the combustion chamber.

If you hav a high compression engine, you should run a fuel with a higher octane, the compression of the engine will not make it hot enough to "explode".

[Grassman]

I agree with jaclawn. The higher octane level helps reduce preignition wich in turn extends the engines life. I use it for peace of mind.

[GrassMaster]

Hello Everybody:

It has been my understanding that you always burn the low octane gas in these small air cooled engines? At least that's what most OEM's tell you?

Yes the high octane gas will make the engine perform better, but you sacrifice some of your engine life to do this? Because it is running much hotter. So I personally would stick to low octane gas.

Over the next period of few months I will be contacted by the different OEM's & I will ask them about this.

In most all cases the engine knocking, pinging & trying to run after it is shut off is caused by the engine ideling to fast & Kohlar has commented to the dealers quite a few times about this. Since Kohlar engines have this problem more than others. Another thing is pull those heads & look for carbon build up, a few of the Engine OEM's recommend that you pull the heads after I think 250 hours & remove the Carbon build up on Pistons & Valves. You want to see some damage let a tiny piece of carbon get between yo Piston & Cylinder wall, it's as bad or worse than dirt!

Like I say I will ask & find out? If you have a concerne about this, contact one of the Techs at the OEM of your engine manfacture & ask them. Then get their name & date it. That way if there is a problem later on down the road, you got the Techs name & time they told you.

That's all I know & I could be wrong?

[Twotoros]

I posted earlier of having trouble with my toro 2-strokes . My dealer contacted his rep and to make a long story short said I should switch to high oct. Because of new emission stadards running low grade causes problems especially in warmer dry regions such as the one I live in. Automatic price increase in fuel . Let's see that puts me at 2$'s a gal or better now.

[awm]

I always use high oct. with excellent results.
My post was about new info ( to me) on
honda engines. thanks tm

[lawrence stone]

If you use oil refined from crude at 50 to 1 you will have problems with two cycle engines.

Two cycle engies have compression ratios of 6-7 to 1.
High octane fuel is a complete waste of money.